English العربية کوردی

ئەز   Hussien Ismail Salim

Assistant Professor

Specialties

Fabrication of Thin Film solar cells grown by low-cost electrodeposition technique

hussein.salim@uoz.edu.krd
07504573858
Iraq , Zakho
1
Awards
14
Published Journal Articles
2
Thesis
2
Training Course

0
Book Chapter
14
Conference
8
Presentation
4
Workshop

Education

PhD

Materials and Engineering Research Institute (MERI) لە Sheffield Hallam University

2016

M.Sc.

Physics لە Duhok

2009

B.Sc.

Duhok لە Duhok

2004

Membership


2019

2019-05-23,current
ICOASE Committe

Member

2014

2014-02-15,2017-02-15
Associate Member

IOP Institute of Physics

Academic Title

Assistant Professor

2020-06-08

Awards

Certificate of appreciation

2018-09
University of Zakho

In recognition of having the maximum record of citation

 2018

Published Journal Articles

SJUOZ (Issue : 4) (Volume : 8)
The Effects Of N-GaAs Substrate Orientations on The Electrical Performance of PANI/N-GaAs Hybrid Solar Cell Devices

This paper reports the fabrication and electrical characterization of hybrid organic-inorganic solar cell based on... See more

This paper reports the fabrication and electrical characterization of hybrid organic-inorganic solar cell based on the deposition of polyaniline (PANI) on n-type GaAs substrate with three different crystal orientations namely Au/PANI/(100) n-GaAs/(Ni-Au), Au/PANI/(110) n-GaAs/(Ni-Au), and Au/PANI/(311)B n-GaAs/(Ni-Au) using spin coating technique. The effect of crystallographic orientation of n-GaAs on solar cell efficiency of the hybrid solar cell devices has been studied utilizing current density-voltage (J-V) measurements under illumination conditions. Additionally, the influence of planes of n-GaAs on the diode parameters of the same devices has been investigated by employing current-voltage (I-V) characteristics in the dark conditions at room temperature. The experimental observations showed that the best performance was obtained for solar cells fabricated with the structure of Au/PANI/(311)B n-GaAs/(Ni-Au). The open-circuit voltage (Voc), short circuit current density (Jsc), and solar cell efficiency () of the same device were shown the values of 342 mV, 0.294 mAcm-2, 0.0196%, respectively under illuminated condition. All the solar cell characteristics were carried out under standard AM 1.5 at room temperature. Also, diode parameters of PANI/(311)B n-GaAs heterostructures were calculated from the dark I-V measurements revealed the lower reverse saturation current (Io) of 3.0×10-9A, higher barrier height () of 0.79 eV and lower ideality factor (n) of 3.16.

 2020-12
Journal of Materials Science: Materials in Electronics (Springer) (Issue : 5) (Volume : 31)
The effect of growth technique on the characteristic properties of CdS layers for solar cell applications

The effects of two different growth methods including electrodeposition (ED) (two-electrode configuration) and chemical bath... See more

The effects of two different growth methods including electrodeposition (ED) (two-electrode configuration) and chemical bath deposition (CBD) on the characteristic properties of CdS thin-films were explored and reported. The electrodeposited CdS (ED-CdS) layers were grown on glass/fluorine-doped tin oxide (FTO) substrates using acidic and aqueous solution containing 0.3 M of thiourea (SC(NH2)2) and 0.2 M of cadmium chloride hydrate (CdCl2.xH2O). The chemical bath deposited CdS (CBD-CdS) layers were also grown on glass/FTO substrates using alkaline and aqueous solution containing 4 × 10–3 M of cadmium acetate dihydrate (Cd(CH3CO2)2.2H2O), 20 × 10–3 M of thiourea (TU) and 6 × 10–2 M ammonium acetate (NH4C2H3O2). The deposited CdS thin-films were characterised using X-ray diffraction (XRD), UV–Visible spectrophotometer (UV–Vis), scanning electron microscopy (SEM), and photoelectrochemical (PEC) cell measurement to study their structural, optical, morphological, and electrical properties, respectively. The structural study shows the polycrystalline nature of the ED-CdS and CBD-CdS thin-films with stable hexagonal phase after heat treatment. The preferred orientation for both ED-CdS and CBD-CdS layers was along (002) hexagonal plane. The average crystallite size of CdS thin-films grown by both deposition methods were in the range ~ (11–38) nm and ~ (22–53) nm before and after heat treatment, respectively. Optical studies reveal the direct bandgap value of 2.42 eV for the heat-treated ED-CdS and CBD-CdS layers which correspond to the bulk bandgap of CdS (hexagonal phase). Morphological studies depict the average grain sizes in the range ~ (90–260) nm for the CdS thin-films. The PEC cell measurements show that the CdS layers grown by both ED and CBD methods were n-type in electrical conduction before and after heat treatment. No visible precipitations of elemental S or CdS particles were observed in the deposition electrolyte of ED-CdS showing a stable bath using TU precursor during the growth. The solar cells fabricated using CBD-CdS showed better performance as compared to the devices fabricated using ED-CdS due to the uniform coverage of FTO surface and better fill factor (FF).

 2020-01
Journal of Materials Science: Materials in Electronics (Issue : 16) (Volume : 29)
The influence of ZnS crystallinity on all-electroplated ZnS/CdS/CdTe graded bandgap device properties

Electrodeposition of zinc sulphide (ZnS) was achieved from electrolytic bath containing zinc sulphate monohydrate (ZnSO4·H2O)... See more

Electrodeposition of zinc sulphide (ZnS) was achieved from electrolytic bath containing zinc sulphate monohydrate (ZnSO4·H2O) and ammonium thiosulphate ((NH4)2S2O3) in a two-electrode electroplating configuration. The cyclic voltammetric studies show that ZnS layers can be electroplated between (1350 and 1550) mV. The grown layers were characteristically explored for their structural, optical, morphological and electronic properties using X-ray diffraction (XRD) and Raman spectroscopy, UV–Visible spectrophotometry, scanning electron microscopy (SEM), photoelectrochemical (PEC) cell and DC conductivity measurements respectively. The structural analysis shows that crystalline ZnS can be deposited within a narrow cathodic deposition range between (1420 and 1430) mV. The UV–Visible spectrophotometry shows that the bandgap of both as-deposited and heat-treated ZnS films are in the range of ~ (3.70 to 3.90) eV. The SEM shows small grains depicting the wetting property of ZnS. The PEC results show that the electroplated ZnS below 1425 mV is p-type and above 1425 mV is n-type under both as-deposited and heat treated condition. The DC conductivity shows that the highest resistivity is at the inversion growth voltage (Vi) for the ZnS layers. The glass/FTO/n-ZnS/n-CdS/n-CdTe/Au devices were fabricated using crystalline-ZnS and amorphous-ZnS buffer layers. The devices were explored using current–voltage (I-V) and capacitance–voltage (C–V) techniques. As expected, devices fabricated with c-ZnS show improved device parameters (ideality factor n = 1.60, depletion width W = 1092 nm, open-circuit voltage Voc=730 mV, short-circuit current density Jsc=34.1 mAcm−2, fill factor FF = 0.57, conversion efficiency η = 14.2%) when compared to device parameters (n = 1.85, W = 900 nm, Voc=720 mV, Jsc=29.9 mAcm−2, FF = 0.52, η = 11.2%) of these devices fabricated with a-ZnS buffer layers.

 2018-06
Journal of Materials Science: Materials in Electronics (Issue : 4) (Volume : 28)
Effect of thickness: a case study of electrodeposited CdS in CdS/ CdTe based photovoltaic devices

The effect of electrodeposition technique on CdS thickness incorporated in CdS/CdTe-based solar cell has been... See more

The effect of electrodeposition technique on CdS thickness incorporated in CdS/CdTe-based solar cell has been investigated using all-electrodeposited g/FTO/n-CdS/ n-CdTe/p-CdTe multilayer device configuration. The optical, morphological and structural properties of the electroplated CdS were investigated for CdS thicknesses between 50 and 200 nm. The observed CdS bandgap ranges between 2.42 and 2.46 eV. The morphological analysis shows full coverage of underlying g/FTO substrate for all CdS thicknesses except for the 50 nm which shows the presence of gap in-between grains. The structural analysis shows a preferred orientation of H(101) for all the CdS thicknesses except the 50 nm thick CdS which shows either a weak crystallinity or an amorphous nature. The fabricated solar cell shows a maximum conversion efficiency of ~11 % using CdS thickness ranging between 100 and 150 nm. These results show that although low CdS thickness is desirable for photovoltaic application, the effect of nucleation mechanism of deposition technique should be taken into consideration.

 2016-10
Journal of Materials Science: Materials in Electronics (Issue : 3) (Volume : 28)
Improvement of composition of CdTe thin films during heat treatment in the presence of CdCl2

CdCl2 treatment is a crucial step in development of CdS/CdTe solar cells. Although this processing... See more

CdCl2 treatment is a crucial step in development of CdS/CdTe solar cells. Although this processing step has been used over a period of three decades, full understanding is not yet achieved. This paper reports the experimental evidence for improvement of composition of CdTe layers during CdCl2 treatment. This investigation makes use of four selected analytical techniques; Photoelectro-chemical (PEC) cell, X-ray diffraction (XRD), Raman spectroscopy and Scanning electron microscopy (SEM). CdTe layers used were electroplated using three Cd precursors; CdSO4, Cd(NO3)2 and CdCl2. Results show the improvement of stoichiometry of CdTe layers during CdCl2 treatment through chemical reaction between Cd from CdCl2 and elemental Te that usually precipitate during CdTe growth, due to its natural behaviour. XRD and SEM results show that the low-temperature (~85 oC) electroplated CdTe layers consist of ~(20–60) nm size crystallites, but after CdCl2 treatment, the layers show drastic recrystallisation with grains becoming a few microns in size. These CdCl2 treated layers are then comparable to high temperature grown CdTe layers by the size of grains.

 2016-10
Materials Research Express (Issue : 9) (Volume : 3)
One-sided rectifying p–n junction diodes fabricated from n-CdS and p-ZnTe:Te semiconductors

The fabrication of a one-sided p–n hetero-junction (HJ) diodes have been successfully carried out using... See more

The fabrication of a one-sided p–n hetero-junction (HJ) diodes have been successfully carried out using both p-type ZnTe and n-CdS semiconductors. Chemical bath deposition (CBD) and electrodeposition (ED) techniques have been used in the deposition of n-CdS and p-ZnTe layers respectively. Before the fabrication of the one-sided p–n HJ diodes, the electrical properties of glass/ FTO/p-ZnTe/Al and glass/FTO/n-CdS/Au rectifying structures were separately studied using capacitance–voltage (C–V ) technique so as to determine the doping density of each of the thin films. The results from C–V analyses showed that p-ZnTe is moderately doped with an acceptor density of 3.55×1015 cm−3 while n-CdS is heavily doped with a donor density of 9.00×1019 cm−3. The heavy doping of n-CdS and moderate doping of p-ZnTe will make the interface between n-CdS and p-ZnTe thin films a one-sided n+p diode. Therefore, to fabricate the CdS/ZnTe hetero-structure, it was ensured that approximately same thickness of CdS and ZnTe thin films being used in the initial experiment to study the electrical properties of glass/FTO/n-CdS/Au and glass/FTO/p-ZnTe/Al were also used in the development of the one-sided n+p junction diodes to obtain more accurate results. The electronic properties of the device structure were studied using both current–voltage (IV ) and C–V measurement techniques. The I–V results show that the one-sided n+p HJ diodes possess good rectifying quality with aseries resistance (Rs) of ∼35 Ω and rectification factors exceeding 102.7 under dark condition. The results of the C–V analyses showed that the acceptor density of the onesided n+p HJ diode is of the order of 1015 cm−3 while the donor density is of the order of 1018 cm−3. The results obtained from this analysisstill showed the moderate doping of p-ZnTe and the degenerate nature of n-CdS.

 2016-09
Ceylon Journal of Science (Issue : 2) (Volume : 45)
Electrodeposition and characterization of as-deposited and annealed CdTe thin films

Thin films of CdTe semiconductor materials were grown on fluorine doped tin oxide (FTO) conducting... See more

Thin films of CdTe semiconductor materials were grown on fluorine doped tin oxide (FTO) conducting glass substrates using the technique of electrodeposition. CdSO4 at high concentrations and CdCl2, TeO2 at low concentrations were used as precursor salts for electrodeposition. The range of deposition potentials was estimated using cyclic voltammetric measurements. The electrical, optical, structural and morphological characteristics of asdeposited and annealed CdTe thin films were characterized using photo-electrochemical (PEC) cell studies, UV-Vis spectrophotometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). These particular samples were converted from n-type into p-type after heat treatment. UV-Vis spectrometric measurements for CdTe layers indicated that, the energy band gaps of 1.45±0.02 eV for both asdeposited and annealed samples which exhibited the required optical property for fabricating CdS/CdTe solar cells. Little increase in (220) and (311) peaks of XRD spectra were observed for annealed layers compared to the as-deposited material. However, annealing exhibited a small reduction of cubic phase preferential orientation (111). The optical transmission for both as-deposited and annealed CdTe samples were about 60% for wavelengths longer than about 850 nm.

 2016-09
Journal of Materials Science: Materials In Electronics (Issue : 7) (Volume : 27)
Electrodeposition and characterisation of CdS thin films using thiourea precursor for application in solar cells

CdS thin films have been successfully electrodeposited on glass/FTO substrates using acidic and aqueous solution... See more

CdS thin films have been successfully electrodeposited on glass/FTO substrates using acidic and aqueous solution of CdCl2.xH2O and thiourea (SC(NH2)2). The electrodeposition of CdS thin films were carried out potentiostatically using a 2-electrode system. The prepared films were characterised using X-ray diffraction, Raman spectroscopy, Scanning electron microscopy, Atomic force microscopy, Photoelectrochemical cell measurements, Electrical resistivity measurements and UV–Vis spectrophotometry to study their structural, compositional, morphological, electrical and optical properties, respectively. The structural studies show that the as-deposited and annealed CdS layers are polycrystalline with hexagonal crystal structure and preferentially oriented along (200) planes. The optical studies indicate that the ED-CdS layers have direct bandgaps in the range (2.53–2.58) eV for the as-deposited and (2.42–2.48) eV after annealing at 400 C for 20 min in air. The morphological studies show the good coverage of the FTO surface by the CdS grains. The average grain sizes for the as-deposited and annealed layers were in the range ~(60–225) nm. These grains or clusters are made out of smaller nano crystallites with the sizes in the range ~(11–33) nm. The electrical resistivity shows reduction as thickness increases. The resistivity values for the as-deposited and annealed layers were in the range (0.82–4.92) 9 105 Xcm. The optimum growth voltage for the CdS thin films was found to be at the cathodic potential of 797 mV with respect to the graphite anode. No visible precipitations of elemental S or CdS particles were observed in the deposition electrolyte showing a stable bath using thiourea during the growth.

 2016-03
Journal of Materials Science: Materials in Electronics (Issue : 5) (Volume : 27)
Study of Fermi level position before and after CdCl2 treatment of CdTe thin films using ultraviolet photoelectron spectroscopy

The CdCl2 treatment used in the development of high efficiency CdTe solar cells is an... See more

The CdCl2 treatment used in the development of high efficiency CdTe solar cells is an essential processing step but remains fully unexplored. What really happens during this treatment is not yet fully understood. The changes in doping concentrations during this processing step are a key parameter to investigate. Determination of the position of the Fermi level (FL) is a good method to explore these changes and therefore photoelectrochemical cell method and ultraviolet photoelectron spectroscopy method have been used to investigate these trends. Four different CdTe layers prepared by electroplating have been used for this investigation. The overall observations indicate the settling down of the FL in the upper half of the bandgap after CdCl2 treatment.

 2016-02
Energies (Issue : 10) (Volume : 8)
Electro-Plating and Characterisation of CdTe Thin Films Using CdCl2 as the Cadmium Source

Cadmium telluride (CdTe) thin films have been successfully prepared from an aqueous electrolyte bath containing... See more

Cadmium telluride (CdTe) thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2)·H2O and tellurium dioxide (TeO2) using an electrodeposition technique. The structural, electrical, morphological and optical properties of these thin films have been characterised using X-ray diffraction (XRD), Raman spectroscopy, optical profilometry, DC current-voltage (I-V) measurements, photoelectrochemical (PEC) cell measurement, scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV-Vis spectrophotometry. It is observed that the best cathodic potential is 698 mV with respect to standard calomel electrode (SCE) in a three electrode system. Structural analysis using XRD shows polycrystalline crystal structure in the as-deposited CdTe thin films and the peaks intensity increase after CdCl2 treatment. PEC cell measurements show the possibility of growing p-, i- and n-type CdTe layers by varying the growth potential during electrodeposition. The electrical resistivity of the as-deposited layers are in the order of 104 Ω·cm. SEM and AFM show that the CdCl2 treated samples are more roughness and have larger grain size when compared to CdTe grown by CdSO4 precursor. Results obtained from the optical absorption reveal that the bandgap of as-deposited CdTe (1.48–1.52) eV reduce to (1.45–1.49) eV after CdCl2 treatment. Full characterisation of this material is providing new information on crucial CdCl2 treatment of CdTe thin films due to its built-in CdCl2 treatment during the material growth. The work is progressing to fabricate solar cells with this material and compare with CdTe thin films grown by conventional sulphate precursors. Keywords: electroplating; cadmium telluride (CdTe); CdCl2 treatment; material characterisation

 2015-09
Energies (Issue : 6) (Volume : 8)
Next Generation Solar Cells Based on Graded Bandgap Device Structures Utilising Rod-Type Nano-Materials

Current solar cells under research and development utilise mainly one absorber layer limiting the photon... See more

Current solar cells under research and development utilise mainly one absorber layer limiting the photon harvesting capabilities. In order to develop next generation solar cells, research should move towards effective photon harvesting methods utilising low-cost solar energy materials. This will lead to reduce the $W−1 figure for direct solar energy conversion to electrical energy. In this work, a graded bandgap solar cell has been designed to absorb all photons from the UV, visible and IR regions. In addition, impurity PV effect and impact ionisation have been incorporated to enhance charge carrier creation within the same device. This new design has been experimentally tested using the most researched MOCVD grown GaAs/AlGaAs system, in order to confirm its validity. Devices with high Voc ~ 1175 mV and the highest possible FF ~ (0.85–0.87) have been produced, increasing the conversion efficiency to ~20% within only two growth runs. These devices were also experimentally tested for the existence of impurity PV effect and impact ionisation. The devices are PV active in complete darkness producing over 800 mV, Voc indicating the harvesting of IR radiation from the surroundings through impurity PV effect. The quantum efficiency measurements show over 140% signal confirming the contribution to PV action from impact ionisation. Since the concept is successfully proven, the low-cost and scalable electrodeposited semiconducting layers are used to produce graded bandgap solar cell structures. The utilisation of nano- and micro-rod type materials in graded bandgap devices are also presented and discussed in this paper. Preliminary work on glass/FTO/n-ZnS/n-CdS/n-CdTe/Au graded bandgap devices show 10%–12% efficient devices indicating extremely high Jsc values ~48 mA·cm−2, showing the high potential of these devices in achieving higher efficiencies. The detailed results on these low-cost and novel graded bandgap devices are presented in a separate publication. Keywords: graded bandgap structures; next generation solar cells; impurity PV effect; impact ionisation; nano-materials

 2015-06
Journal of Materials Science: Materials in Electronics (Issue : 7) (Volume : 26)
Effects of CdCl2 treatment on deep levels in CdTe and their implications on thin film solar cells: a comprehensive photoluminescence study

This work is aimed at studying defect level distributions in the bandgap of CdTe thin... See more

This work is aimed at studying defect level distributions in the bandgap of CdTe thin films, used for solar cell development. In particular, the effects of CdCl2 treatment on the defect levels are the main objectives of this research. Four different nearly optimised CdTe thin films were electroplated using three different Cd-precursors (CdSO4, Cd(NO3)2 and CdCl2), and bulk CdTe wafers purchased from industry were studied using low temperature photoluminescence. The finger prints of defects, 0.55 eV below the conduction band down to the valence band edge were investigated. In all of the CdTe layers, four electron trap levels were observed with varying intensities but at very similar energy positions, indicating that the origin of these defects are mainly from native defects. CdCl2 treatment and annealing eliminates two defect levels completely and the mid-gap recombination centres are reduced drastically by this processing step. The optical bandgap of all four as-deposited CdTe layers is ~1.50 eV, and reduces to ~1.47 eV after CdCl2 treatment. The material grown using the CdCl2 precursor seems to produce CdTe material with the cleanest bandgap, most probably due to the built-in CdCl2 treatment while growing the material.

 2015-05
Journal of Materials Science: Materials in Electronics (Issue : 5) (Volume : 26)
Electrodeposition of CdTe thin films using nitrate precursor for applications in solar cells

Cadmium telluride (CdTe) thin films have been electrodeposited (ED) on glass/fluorine-doped tin oxide (FTO) substrates... See more

Cadmium telluride (CdTe) thin films have been electrodeposited (ED) on glass/fluorine-doped tin oxide (FTO) substrates using simplified two-electrode system in acidic and aqueous solution containing Cd(NO3)2 4H2O and TeO2. The X-ray diffraction (XRD), optical absorption, photoelectrochemical (PEC) cell measurements, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been carried out to study the structural, optical, electrical and morphological properties of the CdTe layers. The XRD study shows that the ED-CdTe layers are polycrystalline with cubic crystal structure. Results obtained from optical absorption reveal that the bandgaps of the as-deposited and the CdCl2 treated CdTe layers are in the ranges ~1.50 to ~1.54 eV and ~1.46 to ~1.51 eV, respectively. Observation from PEC measurements indicates a p-, i- and n-type electrical conductivity for as-deposited CdTe layers grown in the cathodic voltage range (1,247–1,258) mV. The SEM images indicate noticeable change in CdTe grain size from ~85 to ~430 nm after CdCl2 treatment with uniform surface coverage of the glass/FTO substrate. The TEM images show the columnar growth structure for as-deposited and CdCl2 treated CdTe layers. The TEM images also indicate an increase in grain’s diameter from ~50 to ~200 nm after CdCl2 treatment.

 2015-02
Coatings (Issue : 3) (Volume : 4)
Fabrication of CdS/CdTe-Based Thin Film Solar Cells Using an Electrochemical Technique

Thin film solar cells based on cadmium telluride (CdTe) are complex devices which have great... See more

Thin film solar cells based on cadmium telluride (CdTe) are complex devices which have great potential for achieving high conversion efficiencies. Lack of understanding in materials issues and device physics slows down the rapid progress of these devices. This paper combines relevant results from the literature with new results from a research programme based on electro-plated CdS and CdTe. A wide range of analytical techniques was used to investigate the materials and device structures. It has been experimentally found that n-, i- and p-type CdTe can be grown easily by electroplating. These material layers consist of nano- and micro-rod type or columnar type grains, growing normal to the substrate. Stoichiometric materials exhibit the highest crystallinity and resistivity, and layers grown closer to these conditions show n → p or p → n conversion upon heat treatment. The general trend of CdCl2 treatment is to gradually change the CdTe material’s n-type electrical property towards i-type or p-type conduction. This work also identifies a rapid structural transition of CdTe layer at 385 ± 5 °C and a slow structural transition at higher temperatures when annealed or grown at high temperature. The second transition occurs after 430 °C and requires more work to understand this gradual transition. This work also identifies the existence of two different solar cell configurations for CdS/CdTe which creates a complex situation. Finally, the paper presents the way forward with next generation CdTe-based solar cells utilising low-cost materials in their columnar nature in graded bandgap structures. These devices could absorb UV, visible and IR radiation from the solar spectrum and combine impact ionisation and impurity photovoltaic (PV) effect as well as making use of IR photons from the surroundings when fully optimised. Keywords: electrodeposition; CdS/CdTe; thin film solar cells; graded bandgaps; nano-materials; next generation solar cells

 2014-06

Thesis

2016-06-01
Multilayer Solar Cells Based on CdTe Grown From Nitrate Precursor

PhD

 2016
2009-03-17
Modeling One-Dimensional High Temperature Superconducting Grain Boundary Josephson Junction Array and using it as A Magnetometer

M.Sc.

 2009

Conference

BACG, United Kingdom
 2020-02
Conference

Attendance

Proceedings of the International Postgraduate Research Conference, University of Kelaniya, Kelaniya, Sri Lanka.
 2015-12
Growth of CdS and CdTe thin film semiconductors and fabrication of CdS/CdTe solar cells

Thin films of CdS and CdTe semiconductor materials were electrodeposited onto glass/fluorine doped tin oxide conducting glass surfaces using a potentiostat/galvanostat equipped with a three electrode cell. Aqueous electrolytic bath containing CdCl2 and (NH4)2S2O3 was... See more

Thin films of CdS and CdTe semiconductor materials were electrodeposited onto glass/fluorine doped tin oxide conducting glass surfaces using a potentiostat/galvanostat equipped with a three electrode cell. Aqueous electrolytic bath containing CdCl2 and (NH4)2S2O3 was used for the electrodeposition of CdS thin films. CdTe thin films were electrodeposited onto glass/FTO/CdS substrates from aqueous solution having high concentrations of CdSO4 and low concentrations of TeO2 and CdCl2. The glass/FTO/CdS/CdTe/Cu-Au solar cell devices were prepared by thermal evaporation of Cu and Au on CdTe surface. CdS films grown were annealed at ~400 °C for 15 minutes in air and photo-electro chemical (PEC) cell measurements were performed to identify the electrical conductivity type. Both as-deposited and annealed CdS layers were identified as n-type in electrical conduction. CdS thin films were shown enhanced PEC responses upon heat treatment. The respective band gap values for as-deposited and heat treated CdS were 2.35±0.05 eV and 2.40±0.05 eV which were close to the band gap of bulk CdS. XRD analysis of as-deposited CdS layers revealed the presence of hexagonal CdS materials with the major peak arising from (002) plane. Following the CdTe deposition on glass/FTO/CdS substrate, the surface of CdTe layers were coated with a 0.1% CdCl2 solution and structures were annealed at ~400°C for 10 minutes in air. Band gaps for CdTe layers were found to be 1.45±0.02 eV for both as-deposited and annealed samples which exhibited the band gap of bulk CdTe. There was a little improvement in cubic (220) and (311) peaks of XRD spectra of annealed CdTe layers compared to the as-deposited material, but annealing exhibited a small reduction of cubic phase preferential orientation (111). SEM images showed that CdS and CdTe layers were fairly uniform. The fabricated solar cell devices showed the efficiency of 2.1% with Voc ~330 mV, Jsc~20 mA cm-2 and FF~33% under the illumination of air mass (AM) 1.5 conditions (100 mW/cm2 , 1 Sun).

UK Semiconductors & UK Nitrides Consortium Summer Meeting, Sheffield, United Kingdom
 2015-07
Effect of CdCl2 and CdCl2+CdF2 treatment on the structural, morphological and optical properties of electrodeposited CdTe thin films

CdTe thin films were electrodeposited (ED) using acidic aqueous solution containing 1.0 M Cd(NO3)2 4H2O and 1.0 mM TeO2. The deposition of the CdTe thin films were carried out cathodically using 2-electrode system on the... See more

CdTe thin films were electrodeposited (ED) using acidic aqueous solution containing 1.0 M Cd(NO3)2 4H2O and 1.0 mM TeO2. The deposition of the CdTe thin films were carried out cathodically using 2-electrode system on the glass/FTO substrate. The ED-CdTe layers were heat treated with CdCl2 and CdCl2+CdF2 at three different temperatures of 385oC, 420oC and 450oC and results were compared with the as grown layers. The structural, morphological and optical properties of the CdTe layers were carried out using X-ray diffraction (XRD), Scanning electron microscopy (SEM) and optical absorption. The observation reveals the drastic improvements in the structural, morphological and optical properties of ED-CdTe thin films after annealing at 450oC in the presence of CdCl2 and CdCl2+CdF2 treatment as compared to annealing temperature of 385oC and 420oC. Keywords: Electrodeposition, CdTe, thin film, semiconductor, CdCl2 & CdF2

Proceedings of the 11th Photovoltaic Science, Applications and Technology Conference C97 (PVSAT-11), University of Leeds.
 2015-04
Next Generation Solar Cells Based on Graded Bandgap Devices Utilising Rod-type Electroplated Nano-Materials

Current solar cells under research and development utilise mainly one absorber layer limiting the photon harvesting capabilities. In order to develop next generation solar cells, research should move towards effective photon harvesting methods utilising low-cost... See more

Current solar cells under research and development utilise mainly one absorber layer limiting the photon harvesting capabilities. In order to develop next generation solar cells, research should move towards effective photon harvesting methods utilising low-cost solar energy materials. This will lead to reduce the $W−1 figure for direct solar energy conversion to electrical energy. In this work, a graded bandgap solar cell has been designed to absorb all photons from the UV, visible and IR regions. In addition, impurity PV effect and impact ionisation have been incorporated to enhance charge carrier creation within the same device. This new design has been experimentally tested using the most researched MOCVD grown GaAs/AlGaAs system, in order to confirm its validity. Devices with high Voc ~ 1175 mV and the highest possible FF ~ (0.85–0.87) have been produced, increasing the conversion efficiency to ~20% within only two growth runs. These devices were also experimentally tested for the existence of impurity PV effect and impact ionisation. The devices are PV active in complete darkness producing over 800 mV, Voc indicating the harvesting of IR radiation from the surroundings through impurity PV effect. The quantum efficiency measurements show over 140% signal confirming the contribution to PV action from impact ionisation. Since the concept is successfully proven, the low-cost and scalable electrodeposited semiconducting layers are used to produce graded bandgap solar cell structures. The utilisation of nano- and micro-rod type materials in graded bandgap devices are also presented and discussed in this paper. Preliminary work on glass/FTO/n-ZnS/n-CdS/n-CdTe/Au graded bandgap devices show 10%–12% efficient devices indicating extremely high Jscvalues ~48 mA·cm−2, showing the high potential of these devices in achieving higher efficiencies.

Proceedings of the 11th Photovoltaic Science, Applications and Technology Conference C97 (PVSAT-11), University of Leeds, Leeds, United Kingdom.
 2015-04
Cathodic electrodeposition of CdS thin films from thiourea precursor for solar cell applications

Cadmium sulphide (CdS) thin films have been electrodeposited on glass/FTO substrate using a 2-electrode system from combination of thiourea (CH4N2S) and cadmium chloride hydrate (CdCl2 xH2O) precursors. The thin films were characterised using X-ray diffraction... See more

Cadmium sulphide (CdS) thin films have been electrodeposited on glass/FTO substrate using a 2-electrode system from combination of thiourea (CH4N2S) and cadmium chloride hydrate (CdCl2 xH2O) precursors. The thin films were characterised using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Photoelectrochemical (PEC) cell and Optical absorption to study their structural, morphological, electrical and optical properties. XRD results show that the layers are polycrystalline in nature having hexagonal crystal structure with preferred orientation along (200) plane. SEM spectra indicate an increase in grain size from ~100 nm to ~300 nm after heat treatment. The increase in the magnitude of the PEC signal was observed after CdCl2 heat treatment as compared to the as-deposited layers. Observation from optical absorption reveals that the bandgap values of thin films lies in the range of 2.22 to 2.58 eV. In general, after normal annealing in air and CdCl2 heat treatment bandgap values improve and shifts close to the bulk bandgap value of CdS (2.42 eV). Work is continuing to optimise the electronic quality of these layers for incorporation in thin film solar cells.

Proceedings of the 11th Photovoltaic Science, Applications and Technology Conference C97 (PVSAT-11), University of Leeds, Leeds, United Kingdom.
 2015-04
Electrodeposition of CdTe thin films using chloride precursor for the application in solar cells

Cadmium telluride (CdTe) thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2).H2O and tellurium dioxide(TeO2) using electrodeposition technique. The structural, electrical, microstructuraland opticalproperties of these thin films have been... See more

Cadmium telluride (CdTe) thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2).H2O and tellurium dioxide(TeO2) using electrodeposition technique. The structural, electrical, microstructuraland opticalproperties of these thin films have been characterized using XRD, photo-electro-chemical (PEC) cell, D.C. conductivitymeasurements,SEM and UV-Vis spectrophotometry. It is observed that the bestcathodic potential is698mVwith respect to standard calomel electrode. The work is progressing to fabricate solar cells and compare with CdTe, grown by conventional sulphate precursors .

29th European Photovoltaic Solar Energy Conference and Exhibition, Amsterdam, Netherlands (EU PVSEC)
 2014-09
Development of InxSey Buffer Layers for Application in CdTe Based Thin Film Solar Cells

Poster

UK Semiconductors & UK Nitrides Consortium Summer Meeting, Sheffield Hallam University, Sheffield, United Kingdom.
 2014-07
Grwoth of CdTe thin film by electrodeposition method using cadmium nitrate precursor

Electrodeposition (ED) of CdTe thin films are usually grown using cadmium sulfate (CdSO4) as the precursor for Cd ions. In this work CdTe thin film has been electrodeposited on glass/FTO substrate from cadmium nitrate (Cd(NO3)2.4H2O)... See more

Electrodeposition (ED) of CdTe thin films are usually grown using cadmium sulfate (CdSO4) as the precursor for Cd ions. In this work CdTe thin film has been electrodeposited on glass/FTO substrate from cadmium nitrate (Cd(NO3)2.4H2O) as the precursor for Cd ions using simplified 2-electrode system. Both asdeposited & CdCl2-treated layers were characterised using XRD, PEC, SEM and Optical absorption. Before the growth and process optimisation, the initial solar cells device structures of glass/FTO/CBD-CdS/ED-CdTe/Au fabricated with the electrodeposited CdTe layers show PV activity with solar cell output parameters of V oc = 605 mV, Jsc= 25.5 mAcm-2, FF = 0.41, and η = 6.3%. The work is progressing to develop the devices based on this material.

Proceeding of the 10th Photovoltaic Science, Application and Technology (PVSAT-10), Loughborough University, Loughborough, UK
 2014-04
Electrodeposition of CdTe Thin Film Solar Cells Using Cadmium Nitrate Precursor

Electrodeposition (ED) of CdTe thin films are usually grown using cadmium sulfate (CdSO4) as the precursor for Cd ions. In this work CdTe thin film has been electrodeposited on glass/FTO substrate from cadmium nitrate (Cd(NO3)2.4H2O)... See more

Electrodeposition (ED) of CdTe thin films are usually grown using cadmium sulfate (CdSO4) as the precursor for Cd ions. In this work CdTe thin film has been electrodeposited on glass/FTO substrate from cadmium nitrate (Cd(NO3)2.4H2O) as the precursor for Cd ions using simplified 2-electrode system. Both asdeposited & CdCl2-treated layers were characterised using XRD, PEC, SEM, TEM and Optical absorption. Before the growth and process optimisation, the initial solar cells device structures of glass/FTO/CBD-CdS/ED-CdTe/Au fabricated with the electrodeposited CdTe layers show PV activity with solar cell output parameters of Voc = 605 mV, Jsc= 25.5 mAcm-2, FF = 0.41, and η = 6.3%. The work is progressing to develop the devices based on this material.

2nd International Conference on Solar Energy Materials, Solar Cells and Solar Energy Applications (SOLAR ASIA), Willayah Persekutuan, Malaysia.
 2013-08
Electrodeposition and characterization of polyaniline for development of organic/inorganic hybrid solar cells

Poster

UK Semiconductors & UK Nitrides Consortium Summer Meeting, Sheffield, United Kingdom.
 2013-07
Development of Polyaniline as a pinhole plugging layer in CdS/CdTe solar cells

Poster

Proceedings of the 9th Photovoltaic Science, Applications and Technology Conference C95, , (2013) 79-82At: Swansea, United Kingdom
 2013-06
Thin film photovoltaic solar cells with nano- and micro-rod type II-VI semiconducting materials grown by electroplating

Low-cost electroplating has been used to deposit thin layers of ZnS, CdS and CdTe. Results of scanning electron microscopy (SEM) and 3D atomic force microscopy (3D-AFM) reveal that the window materials grown on glass/FTO substrates... See more

Low-cost electroplating has been used to deposit thin layers of ZnS, CdS and CdTe. Results of scanning electron microscopy (SEM) and 3D atomic force microscopy (3D-AFM) reveal that the window materials grown on glass/FTO substrates consists of uni-directional and compact nano-rods and the absorber material grown on glass/FTO/CdS consists of rods or columnar-shaped grains with much larger cross-sections. Fully processed glass/FTO/ZnS/CdS/CdTe/Metal structures show varying photovoltaic parameters exhibiting up to 10.4% conversion efficiencies with excessively large Jsc values arising due to existence of rod-type material structures in nano-scale. Advantages and disadvantages of these device structures are presented in this paper.

39th IEEE Photovoltaic Specialist Conference, Florida, United States
 2013-06
Thin film photovoltaic solar cells with nano- and micro-rod type II-VI semiconducting materials grown by electroplating.

Low-cost electroplating has been used to deposit thin layers of ZnS, CdS and CdTe. Results of scanning electron microscopy (SEM) and 3D atomic force microscopy (3D-AFM) reveal that the window materials grown on glass/FTO substrates... See more

Low-cost electroplating has been used to deposit thin layers of ZnS, CdS and CdTe. Results of scanning electron microscopy (SEM) and 3D atomic force microscopy (3D-AFM) reveal that the window materials grown on glass/FTO substrates consists of uni-directional and compact nano-rods and the absorber material grown on glass/FTO/CdS consists of rods or columnar-shaped grains with much larger cross-sections. Fully processed glass/FTO/ZnS/CdS/CdTe/Metal structures show varying photovoltaic parameters exhibiting up to 10.4% conversion efficiencies with excessively large Jsc values arising due to existence of rod-type material structures in nano-scale. Advantages and disadvantages of these device structures are presented in this paper (2) (PDF) Thin film photovoltaic solar cells with nano- and micro-rod type II-VI semiconducting materials grown by electroplating. Available from: https://www.researchgate.net/publication/262041660_Thin_film_photovoltaic_solar_cells_with_nano-_and_micro-rod_type_II-VI_semiconducting_materials_grown_by_electroplating [accessed Mar 02 2019].

4th Association of Professional Sri Lankans Convention, APSL - Research Symposium (APSL-RS), Sheffield, United Kingdom
 2012-11
Electroplating of semiconductor materials for photovoltaic and optoelectronic device applications

Poster

Presentation

University of Zakho
2020-12
Oral Presentation

Chemical Bath Deposited (CBD) CdS for Solar Cell Application

 2020
University of Zakho
2019-12
Oral Presentation

The Effect of Growth Technique on The Characteristic Properties of CdS Thin-film

 2019
University of Zakho
2019-12
Oral Presentation

The effect of growth technique on the characteristics properties of CdS thin films

 2019
University of Zakho
2018-12
Oral Presentaion

Effects of CdCl2 & CdCl2+CdF2 treatment on the structural, optical, morphological and performance of the Electrodeposited CdTe-based thin-film solar cells at different temperatures

 2018
University of Zakho
2018-10
Oral Presentation

Application of Nanostructure

 2018
University of Zakho
2016
Oral Presentaion

Thin film solar cells based on electrodeposited CdTe using cadmium nitrate precursor

 2025
Sheffield Hallam University, United Kingdom
2014
Oral Presentation

Study of Thin Film Solar Cells Based On Electrodeposited CdTe Using Nitrate Precursor

 2025
Sheffield Hallam University, United Kingdom
2013-11
Oral Presentation

Study of Thin Film Solar Cells Based On Electrodeposited CdTeUsing Nitrate Precursor

 2013

Workshop

University of Zakho
2019-04
Implementation of Bologna Process at University of Zakho

Directorate of Training & Development Center

 2019
Sheffield Hallam University, Stoddart Building, Room 7140, City Campus, S1 1WB, United Kingdom
2013-06
Sheffield Hallam and Leeds Metropolitan Universities

Workshop A: How to develop yourself as an academic/teacher, selling your skills to non-academic colleagues. Workshop B: Presenting your research in the arts and humanities, presenting your research in the sciences

 2013
A027 Collegiate Hall, Collegiate Crescent Campus, Sheffield Hallam University, United Kingdom
2012-11
PhD Workshop

Ethics Approval & Research Governance

 2012
Leeds Metropolitan University’s City Campus, Leeds, LS1 3HB، United Kingdom
2012-06
Collaborative Postgraduate Research Conference

Project Managing your research Degree (there’s a lot more to project management than you think!) , Public engagement and the research student, Collaboration – Are You Ready?, Writing, Viva Tips, Employability – Marketing Your Doctoral. Work

 2012

Training Course

2011-03-07,2011-09-23
General English Language

General English Language course

 2011
2010-05-08,2010-06-26
Methods of teaching, Computer and English Language

Methods of teaching, Computer and English Language

 2010