Direct Microscopy Imaging of Nonuniform Carrier Transport in Polycrystalline Cadmium Telluride
Document Type
Article
Publication Date
10-21-2020
Department
Department of Mathematics and Statistics
School or Division
Graduate School of Engineering and Management
Digital Object Identifier
Source Publication
Cell Reports Physical Science
Abstract
Inhomogeneous microscopic carrier transport is difficult to study, but important in many condensed-matter applications. For example, the role of grain boundaries (GBs) in polycrystalline semiconductors has been controversial for 20 years. In cadmium telluride (CdTe) solar cells, electron-beam-induced current (EBIC) measurements consistently demonstrate enhanced current collection along GBs, which is argued as evidence for interpenetrating CdTe p-n current-collection networks critical to high efficiency. Conversely, cathodoluminescence (CL) measurements consistently indicate that GBs are deleterious low-lifetime regions. Here, we apply transport imaging (TI) in conjunction with spatially correlated EBIC, CL, and scanning Kelvin probe force microscopy measurements to understand carrier drift, diffusion, and recombination in polycrystalline CdTe. We simultaneously observe GB potential wells, reduced carrier lifetime at GBs, and seemingly contradictory enhanced GB current collection, and then describe their coexistence with microscopic TI and physical arguments. The results provide visualization of inhomogeneous transport that is critical to understanding and engineering polycrystalline solar technology.
Recommended Citation
Xiao, C., Jiang, C.-S., Blaine, K., Amarasinghe, M., Colegrove, E., Metzger, W. K., Al-Jassim, M. M., Haegel, N. M., & Moutinho, H. (2020). Direct Microscopy Imaging of Nonuniform Carrier Transport in Polycrystalline Cadmium Telluride. Cell Reports Physical Science, 1(10), 100230. 10.1016/j.xcrp.2020.100230
Comments
Author Kevin Blaine was an AFIT PhD student at the time of this article. ( AFIT-ENC-DS-21-J-001, June 2021.)
Copyright: © 2020 The Author(s)
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