| Description |
1 online resource (6 p.) : ill. |
| Series |
NREL/CP ; 5200-50755 |
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Conference paper (National Renewable Energy Laboratory (U.S.)) ; 5200-50755.
|
| System Details |
Full text available via Internet in .pdf format. Adobe Acrobat Reader required. |
| Note |
Title from title screen (viewed Oct. 17, 2011). |
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"July 2011." |
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"Presented at the 37th IEEE Photovoltaic Specialists Conference (PVSC 37), Seattle, Washington, June 19-24, 2011." |
| Summary |
A CdSxTe1-x layer forms by interdiffusion of CdS and CdTe during the fabrication of thin-film CdTe photovoltaic (PV) devices. The CdSxTe1-x layer is thought to be important because it relieves strain at the CdS/CdTe interface that would otherwise exist due to the 10% lattice mismatch between these two materials. Our previous work [1] has indicated that the electrical junction is located in this interdiffused CdSxTe1-x region. Further understanding, however, is essential to predict the role of this CdSxTe1-x layer in the operation of CdS/CdTe devices. In this study, CdSxTe1-x alloy films were deposited by radio-frequency (RF) magnetron sputtering and co-evaporation from CdTe and CdS sources. Both RF-magnetron-sputtered and co-evaporated CdSxTe1-x films of lower S content (x<0.3) have a cubic zincblende (ZB) structure akin to CdTe, whereas those of higher S content have a hexagonal wurtzite (WZ) structure like that of CdS. Films become less preferentially oriented as a result of a CdCl2 heat treatment (HT) at ~400 degrees C for 5 min. Films sputtered in a 1% O2/Ar ambient are amorphous as deposited, but show CdTe ZB, CdS WZ, and CdTe oxide phases after a CdCl2 HT. Films sputtered in O2 partial pressure have a much wider bandgap than expected. This may be explained by nanocrystalline size effects seen previously [2] for sputtered oxygenated CdS (CdS:O) films. Initial PV device results show that the introduction of a directly-deposited CdSxTe1-x alloy layer into the device structure produces devices of comparable performance to those without the alloy layer when a CdCl2 HT is performed. Further investigation is required to determine whether the CdCl2 heat treatment step can be altered or eliminated through direct deposition of the alloy layer. |
| Bibliography |
Includes bibliographical references. |
| Funding |
Sponsored by National Renewable Energy Laboratory contract no. DE-AC36-08GO28308 |
| Subject |
Photovoltaic cells -- Research.
|
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Solar cells -- Research.
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Thin films.
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Cadmium sulfide.
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Cadmium telluride.
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| Added Author |
Duenow, Joel N.
|
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IEEE Photovoltaic Specialists Conference.
|
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National Renewable Energy Laboratory (U.S.)
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| Added Title |
Cadmium sulfide/cadmium telluride solar cells containing directly deposited cadmium sulfide-x telluride 1-x alloy layers |
| Gpo Item No. |
0430-P-04 (online) |
| Sudoc No. |
E 9.17:NREL/CP-5200-50755 |
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