Study of Cu-related Defect States in Single-crystal CdTe
Abstract
We have studied single-crystal CdTe using low-temperature photoluminescence (PL) in an effort to understand the effects of copper on the deep levels, as well as the effect of a bromine methanol (BrMe) etch on subsequent copper diffusion into CdTe. In present polycrystalline CdS/CdTe solar cell technology, the use of a back contact that contains Cu is necessary to produce high-efficiency cells. However, it is not generally understood why Cu is necessary for these devices to function well. In order to obtain further advances in the efficiencies of these solar cells, it is important to know how the back contact process may affect the defect states in CdTe. PL is one tool used to study defect states. However, before PL can be used effectively for polycrystalline CdTe solar cells, relevant spectral features first must be interpreted for single-crystal CdTe. All PL in this study was taken at 4.5 K. We report on PL peaks at 1.40 and 1.45 eV, which are seen only after Cu is diffused into single-crystal CdTe.
- Publication:
-
APS Four Corners Section Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..4CF.S9005C