Cadmium Tin Oxide and Zinc Magnesium Oxide Prepared by Hollow Cathode Sputtering for CdTe Photovoltaics

MRS Advances ◽  
2017 ◽  
Vol 2 (53) ◽  
pp. 3203-3214 ◽  
Author(s):  
Alan E. Delahoy ◽  
Shou Peng ◽  
Payal Patra ◽  
Surya Manda ◽  
Akash Saraf ◽  
...  
Keyword(s):  
Solar Cells ◽  
Hollow Cathode ◽  
Open Circuit ◽  
Window Layer ◽  
Cathode Sputtering ◽  
Conducting Oxides ◽  
Heterojunction Solar Cells ◽  
Conduction Band Offset ◽  
Cdte Solar Cells ◽  
Custom Made

ABSTRACTThis work reports the fabrication and characterization of superstrate-type Zn1-xMgxO/CdTe heterojunction solar cells on both CdxSnyO and commercial SnO2:F transparent conducting oxides (TCOs) in which the ZMO and CTO layers are produced for the first time by hollow cathode sputtering. The sputtering is conducted in a reactive mode using metal or alloyed metal targets fitted to a custom-made linear cathode. It is notable that the CdS buffer layer conventionally employed in CdTe solar cells is entirely replaced by the ZMO window layer. The use of ZMO is found to eliminate the blue loss associated with CdS optical absorption and further results in a higher open-circuit voltage. Key parameters were found to be the conduction band offset at the ZMO/CdTe interface and the ZMO thickness. It was discovered that the ZMO exhibits intense photoluminescence even at room temperature. Most of the solar cells were fabricated in the FTO/ZMO/CdTe configuration although CTO/ZMO/CdTe solar cells were also demonstrated. The CTO was produced with an electron mobility of 46 cm2 V-1s-1 without any post-deposition annealing or treatment.

CdS Window Layer for Large Open Circuit Voltages of Low Environmental-Load CdS/CdTe Solar Cells

2003 ◽  
Vol 763 ◽  
Author(s):  
T. Toyama ◽  
H. Oda ◽  
K. Nakamura ◽  
T. Fujihara ◽  
K. Shimizuand ◽  
...  
Keyword(s):  
Solar Cells ◽  
Mixed Crystal ◽  
Open Circuit ◽  
Window Layer ◽  
Environmental Load ◽  
Layer Width ◽  
Cdte Solar Cells ◽  
Substrate Temperatures ◽  
Open Circuit Voltages ◽  
Cds Crystallites

AbstractThe low ‘environmental-load’ CdS/CdTe solar cells for reducing consumption of Cd compounds have been investigated employing the CdS layers fabricated at various substrate temperatures, TCdS, and a conversion efficiency of 14.1% has been achieved. The nanostructure of CdS crystallites made at different TCdS are compared to the crystallinity of CdS, and CdTe deposited on CdS as well as sulfur fraction in CdTe1-xSx mixed crystal layer unintentionally formed at CdS/CdTe(S) interface. The photovoltaic performances, especially obtained relative high open circuit voltages, are discussed in conjunction with the structural properties as well as electrical properties of the solar cells. The solar cells show a relative high Voc due to the large CdTe grains as well as the narrow depletion layer width. Besides, preventing deterioration of the CdS/CdTe(S) interface is found to be quite effective for achieving high open circuit voltages and fill factors.

scholarly journals The Band Structures of Zn1−xMgxO(In) and the Simulation of CdTe Solar Cells with a Zn1−xMgxO(In) Window Layer by SCAPS

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 291
Author(s):  
Xu He ◽  
Lili Wu ◽  
Xia Hao ◽  
Jingquan Zhang ◽  
Chunxiu Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Conduction Band ◽  
Short Circuit ◽  
Wavelength Region ◽  
Short Circuit Current ◽  
Window Layer ◽  
Short Wavelength Region ◽  
Conduction Band Offset ◽  
Cdte Solar Cells

Wider band-gap window layers can enhance the transmission of sunlight in the short-wavelength region and improve the performance of CdTe solar cells. In this work, we investigated the band structure of In-doped Zn1−xMgxO (ZMO:In) by using first-principles calculations with the GGA + U method and simulated the performance of ZMO:In/CdTe devices using the SCAPS program. The calculation results show that with the increased Mg doping concentration, the band gap of ZMO increases. However, the band gap of ZMO was decreased after In incorporation due to the downwards shifted conduction band. Owing to the improved short circuit current and fill factor, the conversion efficiency of the ZMO:In-based solar cells show better performance as compared with the CdS-based ones. A highest efficiency of 19.63% could be achieved owing to the wider band gap of ZMO:In and the appropriate conduction band offset (CBO) of ~0.23 eV at ZMO:In/CdTe interface when the Mg concentration x approaches 0.0625. Further investigations on thickness suggest an appropriate thickness of ZMO:In (x = 0.0625) in order to obtain better device performance would be 70–100 nm. This work provides a theoretical guidance for designing and fabricating highly efficient CdTe solar cells.

Effect of Interface States on the Open-Circuit Volatage in a-Si:H/c-Si Heterojunction Solar Cells

2012 ◽  
Vol 485 ◽  
pp. 454-456
Author(s):  
Lan E Luo ◽  
Chun Liang Zhong
Keyword(s):  
Open Circuit Voltage ◽  
Minority Carrier ◽  
Interface States ◽  
Open Circuit ◽  
Band Offset ◽  
Heterojunction Solar Cells ◽  
Conduction Band Offset ◽  
Photovoltaic Application ◽  
Critical Issues ◽  
Recombination Centers

The properties of the a-Si:H/c-Si interface are one of the critical issues for the photovoltaic application. The effects of the interface states on the open-circuit voltage VOC were performed by a set of simulations. VOC decreases with Dit increasing, especially at high values of Dit, since the interface states act as recombination centers to decrease the excess minority carrier density in c-Si. Since the conduction band offset ∆EC can saturate part of interface states, VOC increasing with ∆EC increasing.

The Influence of Conduction Band Offset on CdTe Solar Cells

2017 ◽  
Vol 47 (2) ◽  
pp. 1201-1207 ◽  
Author(s):  
Yunfei Chen ◽  
Xuehai Tan ◽  
Shou Peng ◽  
Cao Xin ◽  
Alan E. Delahoy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Conduction Band ◽  
Band Offset ◽  
Conduction Band Offset ◽  
Cdte Solar Cells

scholarly journals Optical Losses of Frontal Layers in Superstrate CdS/CdTe Solar Cells Using OPAL2

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 943
Author(s):  
Nowshad Amin ◽  
Mohammad Rezaul Karim ◽  
Zeid Abdullah ALOthman
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Contact Potential Difference ◽  
Short Circuit Current ◽  
Optical Losses ◽  
Contact Potential ◽  
Conducting Oxides ◽  
Cdte Solar Cells ◽  
First Time ◽  
Defect Densities

In this paper, optical losses in CdS/CdTe solar cells are calculated on the basis of the designated reflective index of various frontal layers using an OPAL2 calculator for the first time. Two types of glass (0.1 mm ultra-thin Schott and 1.1 mm standard borosilicate glass) were assumed to be coated by different Transparent-Conducting-Oxides (TCOs) such as SnO2:F, ZnO:Al, and ITO forming frontal layers for CdS/CdTe solar cells in superstrate configuration. Absorption, reflectance, transmittance, and consequently optical bandgap energies are calculated as a function of common thicknesses, used in the literature. The results show that an increase in TCO thickness led to a decrease in optical band gap as well as an enhancement in contact potential difference, which can deteriorate device performance. The optimum thickness of 100 nm for SnO2:F was calculated, while 200 nm for ZnO:Al and ITO show reasonable optical losses caused by reflections at the interfaces’ and the layer’s absorption. It is seen that 80 to 150 nm CdS on ITO might be an effective range to satisfy a high short circuit current and low defect densities at the CdS/CdTe interface. Finally, a minimum 2 μm thickness for the CdTe on the ultra-thin Schott glass coated by optimum layers can result in the highest short circuit current of 28.69 mA/cm2. This work offers a practical equivalent strategy to be applied for any superstrate solar cells containing TCO and CdS frontal layers.

Band gap optimization of the window layer in silicon heterojunction solar cells

Solar Energy ◽  
2014 ◽  
Vol 108 ◽  
pp. 570-575 ◽  
Author(s):  
C.L. Zhong ◽  
L.E. Luo ◽  
H.S. Tan ◽  
K.W. Geng
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Window Layer ◽  
Heterojunction Solar Cells ◽  
Silicon Heterojunction Solar Cells

scholarly journals The finale of a trilogy: comparing terpolymers and ternary blends with structurally similar backbones for use in organic bulk heterojunction solar cells

2018 ◽  
Vol 6 (39) ◽  
pp. 19190-19200 ◽  
Author(s):  
Mary Allison Kelly ◽  
Qianqian Zhang ◽  
Zhengxing Peng ◽  
Victoria Noman ◽  
Chenhui Zhu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Bulk Heterojunction ◽  
Open Circuit ◽  
Ternary Blends ◽  
Heterojunction Solar Cells ◽  
Bulk Heterojunction Solar Cells ◽  
Open Circuit Voltages

Comparing the efficiency of terpolymers vs. ternary blends, this study focuses on two polymers with structurally similar backbones (monoCNTAZ and FTAZ) yet markedly different open circuit voltages.

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