Numerical Simulation of the Performance Characteristics, Instability, and Effects of Band Gap Grading in Cadmium Telluride Based Photovoltaic Devices
- Iowa State Univ., Ames, IA (United States)
Using computer simulations, the performance of several CdTe based photovoltaic structures has been studied. The advantages and disadvantages of band gap grading, through the use of (Zn,Cd)Te, have also been investigated in these structures. Grading at the front interface between a CdS window layer and a CdTe absorber layer, can arise due to interdiffusion between the materials during growth or due to the intentional variation of the material composition. This grading has been shown to improve certain performance metrics, such as the open-circuit voltage, while degrading others, such as the fill factor, depending on the amount and distance of the grading. The presence of a Schottky barrier as the back contact has also been shown to degrade the photovoltaic performance of the device, resulting in a characteristic IV curve. However, with the appropriate band gap grading at the back interface, it has been shown that the performance can be enhanced through more efficient carrier collection. These results were then correlated with experimental observations of the performance degradation in devices subjected to light and heat stress.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- W-7405-Eng-82
- OSTI ID:
- 797338
- Report Number(s):
- IS-T 2189; TRN: US200215%%334
- Resource Relation:
- Other Information: TH: Thesis (M.S.); Submitted to Iowa State Univ., Ames, IA (US); PBD: 1 May 2001
- Country of Publication:
- United States
- Language:
- English
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