CdTe Solar Cell from Sputtering Method

2012 ◽  
Vol 1447 ◽  
Author(s):  
Tara P. Dhakal ◽  
Lakshmi K. Ganta ◽  
Dino Ferizovic ◽  
Surya Rajendran ◽  
Daniel Vanhart ◽  
...  
Keyword(s):  
Grain Size ◽  
Solar Cell ◽  
Cadmium Chloride ◽  
Cdte Layer ◽  
Drying Process ◽  
Type Layer ◽  
Average Grain Size ◽  
Cdte Films ◽  
P Type ◽  
Clear Increase

ABSTRACTWe report CdTe/CdS solar cell with CdTe layer grown by sputtering method. A controlled etch and anneal process on the sputter-grown CdTe films was performed to increase the average grain size of the film. The process involved dipping the CdTe films in a saturated solution of cadmium chloride (CdCl2) in methanol (2.08 gram in 100 ml) followed by a 30 minute annealing at 400 °C. We performed various experiments on this process by varying the dipping times, drying process and annealing times and analyzed the resultant films using Scanning Electron Microscopy (SEM). We could see a clear increase in grain size from 200 nm to 5 μm after CdCl2 treatment. The process also increased the overall roughness of the sample so that more light is absorbed than reflected. We prepared solar cells using CdTe as p-type layer and CdS as n-type layer. The efficiency of the cell improved from 1.1% to 4.2% after air annealing. The effect of air-annealing is studied by means of quantum efficiency measurement.

Preparation and Properties of CdTe Films on Mo/Glass Substrates

2009 ◽  
Vol 1165 ◽  
Author(s):  
Vello Valdna ◽  
Maarja Grossberg ◽  
Hiie Jaan ◽  
Urve Kallavus ◽  
Valdek Mikli ◽  
...  
Keyword(s):  
Cadmium Chloride ◽  
Radiation Detectors ◽  
Cdte Film ◽  
Chloride Flux ◽  
Type Conductivity ◽  
Coated Glass ◽  
Glass Substrates ◽  
Group I ◽  
Cdte Films ◽  
P Type

AbstractShort-bandgap group II-VI compound cadmium telluride is widely used for the infrared optics, radiation detectors, and solar cells where p-type CdTe is needed. p-type conductivity of CdTe is mainly caused by the chlorine-based A-centers, and in part, by the less stable copper-oxygen complexes. As a rule, CdTe films are recrystallized by the help of a cadmium chloride flux that saturates CdTe with chlorine. In chlorine-saturated CdTe A-centers are converted to isoelectronic complexes that cause resistivity increasement of CdTe up to 9 orders of magnitude. Excess copper and oxygen or group I elements as sodium also deteriorate the p-type conductivity of CdTe like excess chlorine. p-type conductivity of CdTe can be restored e.g. by the vacuum annealing which removes excess chlorine from the film. Unfortunately, treatment that betters p-type conductivity of the CdTe film degrades the junction of the superstrate configuration cells. In this work we investigate possibilities to prepare p-type CdTe films on the molybdenum coated glass substrates. Samples were prepared by the vacuum evaporation and dynamic recrystallization of 6N purity CdTe on the top of Mo-coated glass substrates. Then samples were recrystallized with cadmium chloride flux under tellurium vapour pressure. Results of the test studies on the structure and electronic parameters of samples are presented and discussed.

Effect of Chemical Treatment on the Optical Properties of a Cadmium Telluride Photovoltaic Device Investigated by Spectroscopic Ellipsometry

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Sandeep Kohli ◽  
Venkatesan Manivannan ◽  
James N. Hilfiker ◽  
Patrick R. McCurdy ◽  
Robert A. Enzenroth ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Solar Cell ◽  
Spectroscopic Ellipsometry ◽  
Cadmium Chloride ◽  
Cdte Layer ◽  
Photovoltaic Device ◽  
Band Gaps ◽  
Copper Treatment ◽  
Treated Layer

Spectroscopic ellipsometry has been successfully used to characterize the CdS/CdTe heterojunction solar cell deposited on TEC15 glass. The effects of copper treatment on the optical properties of a cadmium chloride treated photovoltaic device were investigated using ellipsometry. No changes in either the band gaps or critical points of CdTe layer were noticed as a result of copper treatment. The copper treated CdTe layer exhibited a higher refractive index in the visible and longer wavelengths (≤3 eV), as compared with the untreated layer. This was attributed to the increased disorder in the case of copper treated layer.

Critical Electric Field of InGaN p-i-n Solar Cell

2013 ◽  
Vol 284-287 ◽  
pp. 1168-1172
Author(s):  
Der Yuh Lin ◽  
Chao Yu Chi
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
High Efficiency ◽  
Physical Models ◽  
Electric Field Effect ◽  
Type Layer ◽  
P Type

We present a study of electric field effect on the efficiency of GaN/In0.1Ga0.9N p-i-n solar cells by using the advanced physical models of semiconductor devices (APSYS) simulation program. In this study, the electric field strength and other parameters such as optimum thickness of p-type layer and efficiency of GaN/In0.1Ga0.9N p-i-n solar cells with different i-layer thicknesses have been performed. On the basis of simulating results, for a high efficiency solar cell, it is found that the optimum p-type layer concentration is above 4×1016cm-3and the suitable thickness is between 0.1 to 0.2 μm. For different i-layer thickness and p-doping concentrations, a critical electric field (Fc) has been found at 100 kV/cm. It is worth to note that when the electric field strength of i-layer below Fc value, the solar cell efficiency will dramatically decrease. Thus Fc can be seen as an index for acquiring the quality of solar device.

scholarly journals Performance of a Nano PbS/Si Hetrojunction Deposited by Chemical Spray Pyrolysis

2015 ◽  
Vol 51 ◽  
pp. 13-16 ◽  
Author(s):  
Ali M. Mousa ◽  
Karem H. Jawad
Keyword(s):  
Grain Size ◽  
Blue Shift ◽  
Chemical Spray Pyrolysis ◽  
Xrd Pattern ◽  
Glass Substrates ◽  
Current Voltage ◽  
Average Grain Size ◽  
Wide Range ◽  
P Type ◽  
Nanocrystalline Thin Films

Deposition of polycrystalline Lead sulfide nanothin films onto Si and glass substrates at temperatures (200-300 °C) was carried out by chemical spraying route using optimized preparative conditions. The XRD pattern confirmed the formation of PbS semiconducting films with orthorhombic structure. The electrical and optical properties of the nanocrystalline thin films were studied aiming to better understanding for the electrical and opto-electrical properties of a hetrojunction with p-type Si. It was found that, the average grain size of PbS in the films was between 4 nm and 7 nm. The band gap was also calculated from the absorption co-efficient curves and showed a blue shift due to the grain size of the nanoPbS in the films. The current-voltage (I-V) and photoresponse characteristics were obtained with different illumination intensities. The detector exhibits an evident wide-range spectral responsivity

scholarly journals Impedance Spectroscopic Study of p-i-n Type a-Si Solar Cell by Doping Variation of p-Type Layer

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Sunhwa Lee ◽  
Seungman Park ◽  
Jinjoo Park ◽  
Youngkuk Kim ◽  
Hyeongsik Park ◽  
...  
Keyword(s):  
Solar Cell ◽  
Spectroscopic Study ◽  
Type A ◽  
Si Solar Cell ◽  
Type Layer ◽  
P Type

Low Temperature Chemical Synthesis of p-Type SnS Thin Films Suitable for Photovoltaic Structures

2013 ◽  
Vol 209 ◽  
pp. 82-85
Author(s):  
T.H. Patel
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Band Gap ◽  
Room Temperature ◽  
Chemical Compositions ◽  
X Rays ◽  
Average Grain Size ◽  
Sns Thin Films ◽  
P Type ◽  
Deposited Film

SnS thin film has been deposited on glass substrate at room temperature using low cost, environmental friendly chemical bath deposition (CBD) technique. The structural parameters of the deposited film have been investigated through X- ray diffraction measurements. The deposited SnS film found almost crystalline with preferred orientations along (111) planes revealing an orthorhombic phase of herzenbergite SnS structure. The lattice parameters and dislocation density were determined. The average grain size estimated to be ~ 25 nm. The surface morphology of the film examined using scanning electron microscopy (SEM) show uniform granular and any crack or pinhole free deposition of the film. The chemical compositions of the film examined using energy dispersive analysis of x-rays (EDAX) confirmed stoichiometric deposition. The analysis of the optical absorption spectra of the deposited film in the wavelength range of 200-1200 nm indicate that direct allowed transitions are dominant in the film. The direct band gap of the film determined to be ~ 1.92 eV which is higher than those reported earlier for bulk or single crystal SnS, exhibiting quantum size effect at the observed grain size in the film. This value of band gap is promising for possible use of the deposited film as absorption layer in photovoltaic structures like solar cells. The thermoelectric power measurements indicate p-type electrical conductivity of the deposited films. A systematic study on room temperature chemical deposition and characterization of SnS thin films suitable for absorber layer in photovoltaic structures has been reported.

CdTe Films on Mo/Glass Substrates: Preparation and Properties

2008 ◽  
Vol 1123 ◽  
Author(s):  
Vello Valdna ◽  
Maarja Grossberg ◽  
Jaan Hiie ◽  
Urve Kallavus ◽  
Valdek Mikli ◽  
...  
Keyword(s):  
Cadmium Chloride ◽  
Radiation Detectors ◽  
Cdte Film ◽  
Chloride Flux ◽  
Type Conductivity ◽  
Coated Glass ◽  
Glass Substrates ◽  
Group I ◽  
Cdte Films ◽  
P Type

AbstractShort-bandgap group II-VI compound cadmium telluride is widely used for the infrared optics, radiation detectors, and solar cells where p-type CdTe is needed. p-type conductivity of CdTe is mainly caused by the chlorine-based A-centers, and in part, by the less stable copperoxygen complexes. As a rule, CdTe films are recrystallized by the help of a cadmium chloride flux that saturates CdTe with chlorine. In chlorine-saturated CdTe A-centers are converted to isoelectronic complexes that cause resistivity increasement of CdTe up to 9 orders of magnitude. Excess copper and oxygen or group I elements as sodium also deteriorate the p-type conductivity of CdTe like excess chlorine. p-type conductivity of CdTe can be restored e.g. by the vacuum annealing which removes excess chlorine from the film. Unfortunately, treatment that betters ptype conductivity of the CdTe film degrades the junction of the superstrate configuration cells. In this work we investigate possibilities to prepare p-type CdTe films on the molybdenum coated glass substrates. Samples were prepared by the vacuum evaporation and dynamic recrystallization of 6N purity CdTe on the top of Mo-coated glass substrates. Then samples were recrystallized with cadmium chloride flux under tellurium vapour pressure. Results of the test studies on the structure and electronic parameters of samples are presented and discussed.

scholarly journals Microstrucral, Optical and Electrical Characteristics of Cu-doped CdTe Nanocrystalline Films for Desinging of Absorber Layer in Solar Cell Applications

2021 ◽  
Author(s):  
Meshal Alzaid ◽  
N. M. A. Hadia ◽  
M. El-Hagary ◽  
E. R. Shaaban ◽  
wael ahmed
Keyword(s):  
Grain Size ◽  
Solar Cell ◽  
Grain Boundary ◽  
Doping Level ◽  
Cell Structure ◽  
Average Crystallite Size ◽  
Absorber Layer ◽  
Electrical Characteristics ◽  
Cu Doping ◽  
Cdte Films

Abstract This paper reports the microstrcure, optical and electrical characteristics of undoped and Cu doped CdTe nanostructured thin films prepared on glass substrates by electron beam evaporation technique. The Crystallographic study of X-ray diffraction shows that CdTe and Cu doped CdTe films crystallize in the form of a cubic zinc blende structure. Microstructure analysis reveals that as the Cu doping level increases, the average crystallite size increases, while the microstrian decreases due to the improvement of the crystallinty, thereby reducing defects. XRD and AFM investigations confirmed the nanostructure characteristic of undoped and Cu doped films. It was found that the optical band gap energy increases from 1.485 eV to 1.683 eV as the Cu concentration increases from 0 wt. % to 10 wt. %, which may be related to the Burstein-Moss effect. The refractive index is calculated from the Swanepoel envelope method and found to decrease with the increase of the Cu doping due to the decrease in the prolizability. Similarly, the extinction coefficient decreases with the increase of Cu in CdTe matrix. The dc electrical conductivity is found to increase with increasing Cu doping, which is attributed to the increase in the grain size, thereby reducing the scattering of the grain boundary. Furthermore, two conduction mechanisms of the carrier transport in nanostrcutured undoped and Cu doped CdTe films were observed. The low temperature dependence of the conductivity of undoped and Cu doped CdTe nanostructured films is explained based on Mott’s variable range hopping conduction mechanism model (VRH). Interestingly, the calculated values of hopping distance R, the hopping energy W and the the density of states at the Fermi level N(EF) are consistent with the Mott's VRH. Finally, Hall effect measurements show that all the films have p- type conduction behavior. Besides, the results show that as Cu doping level increases, the carrier concentration and the Hall mobility increase due to the decrease in grain boundary scattering with the increase in grain size. Accordingly, it can be concluded that by increasing the Cu doping level in the CdTe film, the conductivity is increased, thereby improving the performance of the CdTe absorber layer in the solar cell structure.

scholarly journals Numerical simulation for optimization of ultra-thin n-type AZO and TiO2 based textured p-type c-Si Heterojunction Solar Cells

2021 ◽  
Author(s):  
Chandan Yadav ◽  
sushil kumar
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Crystalline Silicon ◽  
Low Cost ◽  
Simulation Software ◽  
Heterojunction Solar Cell ◽  
Maximum Efficiency ◽  
Heterojunction Solar Cells ◽  
Type Layer ◽  
P Type

Abstract A maximum efficiency of 17% for ultra-thin n-type AZO layer and 17.5% for ultra-thin n-type TiO2 layer based silicon heterojunction solar cell is reported by optimizing its properties which is much higher than practically obtained efficiency signifying a lot of improvements can be performed to improve efficiency of TiO2/Si and AZO/Si heterojunction solar cell. AZO layer and TiO2 layer is used as n-type emitter layer and crystalline silicon wafer is used as p-type (p-cSi) layer for modelling AZO/Si and TiO2/Si heterojunctions solar cell respectively using AFORS HET automat simulation software. Various parameters like thickness of AZO, TiO2 layer, p-cSi layer, doping concentration of donors (Nd) and effective conduction band density (Nc) are optimized. Finally, texturing at different angle is studied and maximum efficiency is reported at 70 µm thick p-type crystalline Silicon (p-cSi) wafer, that can be very helpful for manufacturing low cost HJ solar cells at industrial scale because of thin wafer and removal of additional processing setup required for deposition of amorphous silicon i-layer. Utilization of TiO2 and Aluminium doped Zinc Oxide as n-type layer and p-cSi as p-type layer can help in producing low cost and efficient heterojunction (HJ) than compared to HJ with intrinsic thin layer HIT solar cells.

Theoretical Studies of InGaN/GaN Multiple Junction Solar Cell with Enhanced Tunneling Junction Diode

2014 ◽  
Vol 895 ◽  
pp. 535-538 ◽  
Author(s):  
Shahzad Hussain ◽  
Ghulam Ali ◽  
Haris Mehmood ◽  
Muhammad Omar ◽  
Tahir Zaidi
Keyword(s):  
Solar Cell ◽  
Tunneling Junction ◽  
Junction Solar Cell ◽  
Type Layer ◽  
Multijunction Solar Cells ◽  
Recent Developments ◽  
Double Junction ◽  
Heavily Doped ◽  
P Type ◽  
Efficient Solar Cell

Recent developments in the growth of InGaN layers made it possible to grow a heavily doped p-type layer with Indium concentration up to 40%. In this work, a tunnel junction based on these developments has been designed with the use of Silvaco TCAD. This diode introduces a low resistive path to the current carriers, effectively adds voltages and encounters the parasitic effects of the stacked sub-cells. A double-junction solar cell is designed based on our interfacing tunnel diode and simulated results are presented in this paper. Remarkable results are achieved comparing to the existing InGaN based multijunction solar cells. A highVocof ~3.1V and conversion efficiency greater than 17.5% has been achieved under AM 1.5. This paper also highlights and discusses the challenges in fabrication of such a highly efficient solar cell.

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