SPLTRAK Abstract Submission
Grain size and texture optimization for high efficiency As-doped CdTe thin film solar cells
Vladislav Kornienko1,2, Ochai Oklobia3, Stuart Irvine3, Steve Jones3, Giray Kartopu3, Ali Abbas1, Yau Yau Tse2, Jake Bowers1, Michael Walls1
1Loughborough University-CREST, Loughborough, United Kingdom
/2Department of Materials - Loughborough University, Loughborough, United Kingdom
/3Centre for Solar Energy (CSER), Swansea, United Kingdom

Cross-sectional analysis of high efficiency thin film CdTe solar cells has been obtained over large areas.  The samples have been prepared using a Xenon-Plasma Focused Ion Beam (Xe-PFIB). The analysis was obtained using large area electron backscatter diffraction (EBSD). The as-deposited and partially activated devices show strong (111) growth texture with high a density of twins in the columnar grains. Three FTO/SnO2/CdZnS/CdTe:As devices with 13.1%, 16.3% and 17% conversion efficiency were selected for the microstructural characterization. The large area analysis revealed non-uniformities in the recrystallization induced by the cadmium chloride activation process.  The analysis confirms the expected dependence on grain size.  It also showed that a strong correlation exists between device efficiency and the randomization of the texture.  Retention of the (111) grain orientation leads to poor efficiency while randomization of the texture correlates to high efficiency. The best device had a multiple of uniform density (mud) value of ~2.