Cu K-edge EXAFS Studies Of CdCl2 Effects On CdTe Solar Cells

2005 ◽  
Vol 865 ◽  
Author(s):  
Xiangxin Liu ◽  
Alvin D. Compaan ◽  
Jeff Terry
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Grain Boundary ◽  
Cdte Thin Film ◽  
X Ray ◽  
Cdte Solar Cells ◽  
Cdte Films ◽  
Chloride Treatment ◽  
P Type ◽  
X Ray Absorption

AbstractThe highest performance CdS/CdTe thin film solar cells are generally completed with a Cucontaining back contact. The copper appears to be critical for achieving heavy p-type doping of the CdTe at the contact to permit the formation of a low resistance contact. In previous extended x-ray absorption fine structure (EXAFS) work we have inferred that most of the Cu in CdTe films resides as Cu2O at the boundaries of CdTe grains in films that have received a chloride treatment in the presence of oxygen, a critical step needed to improve the performance of all CdTe thin-film cells. This has suggested a mechanism for grain boundary passivation in thinfilm CdTe solar cells. We believe most of the diffused Cu decorates grain boundaries as oxides, consistent with the low doping densities typically observed in CdTe solar cells. The significance for grain boundary passivation will be discussed. We also find evidence that the grain-boundary Cu2O in CdCl2 treated CdTe films is unstable and tends to transform to CuO under some stress conditions.

First-principles Study of Back Contact Effects on CdTe Thin Film Solar Cells

2010 ◽  
Vol 1268 ◽  
Author(s):  
Mao-Hua Du
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
First Principles ◽  
Cell Performance ◽  
Thin Film Solar Cells ◽  
Back Contact ◽  
Cdte Thin Film ◽  
Solar Cell Performance ◽  
Cdte Solar Cells ◽  
P Type

AbstractForming a chemically stable low-resistance back contact for CdTe thin film solar cells is critically important to the cell performance. This paper reports theoretical study of the effects of the back contact material, Sb2Te3, on the performance of the CdTe solar cells. First-principles calculations show that Sb impurities in p-type CdTe are donors and can diffuse with low diffusion barrier. There properties are clearly detrimental to the solar cell performance. The Sb segregation into the grain boundaries may be required to explain the good efficiencies for the CdTe solar cells with Sb2Te3 back contacts.

A correlative investigation of grain boundary crystallography and electronic properties in CdTe thin film solar cells

2017 ◽  
Vol 166 ◽  
pp. 108-120 ◽  
Author(s):  
Guillaume Stechmann ◽  
Stefan Zaefferer ◽  
Torsten Schwarz ◽  
Peter Konijnenberg ◽  
Dierk Raabe ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Grain Boundary ◽  
Electronic Properties ◽  
Thin Film Solar Cells ◽  
Cdte Thin Film

Importance of electron current in p-type CdTe in CdS/CdTe thin film solar cells at forward bias

2001 ◽  
Vol 668 ◽  
Author(s):  
Jutta Beier ◽  
Marc Köntges ◽  
Peter Nollet ◽  
Stefaan Degrave ◽  
Marc Burgelman
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Minority Carrier ◽  
Voltage Dependence ◽  
Forward Bias ◽  
Back Contact ◽  
Cdte Solar Cells ◽  
Dependent Behavior ◽  
Measurement Results ◽  
P Type

ABSTRACTIn previous work [1,2], we modeled the cross-over of the I-V curves of thin film CdS/CdTe solar cells in terms of an electron (minority carrier) current in the vicinity of the back contact. In this work, we focus on the necessary extension of this analytical model based on a series of measurement results. Especially the wavelength and voltage dependence of the current at forward bias is illustrated in these measurements. The various possible causes for this kind of behavior are discussed and modeled. The extensions to the previous model, needed to describe the voltage and wavelength dependent behavior of I-V curves of real CdTe/CdS solar cells, are proposed.

scholarly journals Effect ofIn SituThermal Annealing on Structural, Optical, and Electrical Properties of CdS/CdTe Thin Film Solar Cells Fabricated by Pulsed Laser Deposition

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Alaa Ayad Al-mebir ◽  
Paul Harrison ◽  
Ali Kadhim ◽  
Guanggen Zeng ◽  
Judy Wu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Thin Film Solar Cells ◽  
Cdte Thin Film ◽  
Cdte Solar Cells ◽  
Cdte Thin Films

Anin situthermal annealing process (iTAP) has been introduced before the commonex situcadmium chloride (CdCl2) annealing to improve crystal quality and morphology of the CdTe thin films after pulsed laser deposition of CdS/CdTe heterostructures. A strong correlation between the two annealing processes was observed, leading to a profound effect on the performance of CdS/CdTe thin film solar cells. Atomic force microscopy and Raman spectroscopy show that the iTAP in the optimal processing window produces considerable CdTe grain growth and improves the CdTe crystallinity, which results in significantly improved optoelectronic properties and quantum efficiency of the CdS/CdTe solar cells. A power conversion efficiency of up to 7.0% has been obtained on thin film CdS/CdTe solar cells of absorber thickness as small as 0.75 μm processed with the optimal iTAP at 450°C for 10–20 min. This result illustrates the importance of controlling microstructures of CdTe thin films and iTAP provides a viable approach to achieve such a control.

scholarly journals A Theoretical Model for Voltage-Dependent Photocurrent Collection in CdTe Solar Cells

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1615
Author(s):  
Cindy X. Zhao ◽  
Ken K. Chin
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Solar Cells ◽  
Solar Cell ◽  
Theoretical Model ◽  
Output Voltage ◽  
Collection Efficiency ◽  
Cdte Thin Film ◽  
Doping Density ◽  
Cdte Solar Cells

The classic solar cell model assumes that the photo-generated current is a constant, independent of the cell’s output voltage. Experimental data of CdTe solar cells, however, show that the photocurrent collection efficiency decreases with the increase of the cell’s output voltage. In this work, we proposed a theoretical model for the CdTe thin-film cell, which assumes that the loss of photocurrent in the CdTe absorber is primarily due to the minority carrier recombination in the neutral region and at the back contact. By solving the neutral region’s diffusion equation, with proper boundary conditions, we have obtained the analytical expressions of the photocurrent collection efficiency and the cell’s J-V performance. Our theoretical results agree well with the experimental data. According to our theoretical model, the CdTe thin-film solar cell has an optimized p-doping level. A higher doping density may not be always good for a CdTe solar cell due to the reduced depletion width and decreased photocurrent at normal operation voltage, although the higher doping density can improve the open-circuit voltage by increasing built-in voltage.

scholarly journals Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Zhouling Wang ◽  
Yu Hu ◽  
Wei Li ◽  
Guanggen Zeng ◽  
Lianghuan Feng ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Contact Layer ◽  
Buffer Layers ◽  
Antimony Telluride ◽  
X Ray ◽  
Cdte Solar Cells ◽  
Structural And Electrical Properties ◽  
Different Temperatures ◽  
P Type

Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

Sulfur Diffusion In Polycrystalline Thin-Film CdTe Solar Cells

1997 ◽  
Vol 485 ◽  
Author(s):  
M. H. Aslan ◽  
W. Song ◽  
J. Tang ◽  
D. Mao ◽  
R. T. Collins ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Ternary Phase ◽  
Back Contact ◽  
X Ray Diffraction ◽  
Polycrystalline Thin Film ◽  
X Ray ◽  
Cdte Solar Cells ◽  
Sulfur Diffusion

AbstractX-ray diffraction and photoluminescence measurements have been used to characterize the diffusion of S into CdTe during post growth annealing of CdTe solar cells. For anneals at 410°C in the presence of CdCl2, evidence that both a CdTe1 xSx phase and nearly-pure CdTe are present near the back contact is observed. The ternary phase becomes more prominent and the S concentration increases with depth reaching roughly 4–5% near the CdS interface. Much less diffusion is observed at 350°C while for a 460°C anneal, CdTe1-xSx with a S concentration near 5% is found throughout the layer. The presence of CdC12 during the anneal enhances the interdiffusion.

High efficiency CdTe solar cells with a through-thickness polycrystalline CdTe thin film

RSC Advances ◽  
2016 ◽  
Vol 6 (57) ◽  
pp. 52326-52333 ◽  
Author(s):  
Kai Shen ◽  
Zhizhong Bai ◽  
Yi Deng ◽  
Ruilong Yang ◽  
Dezhao Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Liquid Phase ◽  
Growth Mechanism ◽  
High Efficiency ◽  
Cdte Thin Film ◽  
Preferential Growth ◽  
Cdte Solar Cells ◽  
Crystalline Growth

CdTe preferential growth with through-thickness grains has been achieved. A crystalline growth mechanism assisted by an oxide liquid phase is proposed.

scholarly journals Resolving the Evolution of Atomic Layer-Deposited Thin-Film Growth by Continuous In Situ X-Ray Absorption Spectroscopy

2021 ◽  
Author(s):  
Xiaohui Qu ◽  
Danhua Yan ◽  
Ruoshui Li ◽  
Jiajie Cen ◽  
Chenyu Zhou ◽  
...  
Keyword(s):  
Thin Film ◽  
Absorption Spectroscopy ◽  
Film Growth ◽  
Atomic Layer ◽  
Thin Film Growth ◽  
X Ray ◽  
X Ray Absorption
Sign in / Sign up

Export Citation Format

Share Document