Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition. Annual technical report, 20 March 1995--19 March 1996 Page: 4 of 46
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Executive Summary
Objectives
The objective of this project is to develop improved processes for the fabrication of CdTe/CdS
polycrystalline thin film solar cells. The technique we use for the formation of CdTe,
electrodeposition, is a non-vacuum, low-cost technique that is attractive for economic, large-scale
production.
Technical Approach
During the past year, our research and development efforts have focused on several steps that are
most critical to the fabrication of high-efficiency CdTe solar cells. These include the optimization
of CdTeelectrodeposition process, the effect of pre-treatment of CdS substrates, the post-deposition
annealing of CdTe, and back contact formation using Cu-doped ZnTe. Systematic investigations
of these processing steps have lead to better understanding and improved device performances of
the CdTe-based solar cells.
Results
Studies of the growth and properties of CBD CdS thin films. The structural properties of the films
and the growth mechanisms were studied by investigating CdS samples prepared at different
deposition times. A duplex structure with an inner compact layer and an outer porous layer and
three growth stages is consistent with our data. The measurement of refractive index as a function
of deposition time provides a simple way to determine the transition point from compact layer
growth to porous layer growth, which is important for the optimization of CdS growth conditions
in photovoltaic applications. Careful XRD analyses allowed unambiguous determination of crystal
properties.
Effect of CdCl, treatment of CdS films. We investigated the effect of CdC2 treatment of CdS films
on the photovoltaic performance of CdTe solar cells. X-ray diffraction studies indicated that the
diffusion of S into CdTe is qualitatively the same for CdTe/CdS films fabricated with both as-
deposited and CdCl2-treated CdS. A major difference was observed in the extent of Te diffusion into
CdS for the two types of CdS films. Full conversion of CdS into CdS,.,Te, was observed for films
prepared with as-deposited CdS, while the formation of the ternary phase was below the detection
limit for films prepared with CdCl2-treated CdS. Photoluminescence measurements confirmed this
result. The difference in interdiffusion leads to differences in optical transmission of CdS films and
spectral response of CdTe/CdS solar cells. An increase of 2.7 mA/cm2 in short-circuit current
density was observed as a result of improved spectral response in the wavelength range of 500-
600 nm for the CdCl2-treated CdS.
Studies of Cu-doped ZnTe back contact layer. Cu-doped ZnTe was studied as a promising material
for forming stable, low-resistance contacts to the p-type CdTe. Polycrystalline ZnTe films were
formed by vacuum co-evaporation of Cu and ZnTe. The electrical properties were studied
systematically as a function of Cu concentration and annealing temperature. The effects of Cu
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Trefny, J.U. & Mao, D. Polycrystalline thin film cadmium telluride solar cells fabricated by electrodeposition. Annual technical report, 20 March 1995--19 March 1996, report, April 1997; Golden, Colorado. (https://digital.library.unt.edu/ark:/67531/metadc678420/m1/4/: accessed April 24, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.