2134/20608 Ali Abbas Ali Abbas Drew E. Swanson Drew E. Swanson Amit Munshi Amit Munshi Kurt L. Barth Kurt L. Barth Walajabad S. Sampath Walajabad S. Sampath G.D. West G.D. West Jake Bowers Jake Bowers Piotr Kaminski Piotr Kaminski Michael Walls Michael Walls The effect of a post-activation annealing treatment on thin film CdTe device performance Loughborough University 2016 CdTe PV CdCl2 TEM EDX SIMS Mechanical Engineering not elsewhere classified 2016-03-17 13:21:16 Conference contribution https://repository.lboro.ac.uk/articles/conference_contribution/The_effect_of_a_post-activation_annealing_treatment_on_thin_film_CdTe_device_performance/9563654 The cadmium chloride activation treatment of cadmium telluride solar cells is essential for producing high efficiency devices. The treatment has many effects but the most significant is the complete removal of stacking faults in the cadmium telluride grains and the diffusion of Chlorine along the grain boundaries of the device. Chlorine decorates all cadmium telluride and cadmium sulphide grain boundaries and also builds up along the CdTe/CdS junction. . This paper reveals that by annealing devices to temperatures of 400ºC to 480 ºC for times ranging from 30 to 600 seconds in moderate vacuum results in the re-appearance of stacking faults and the removal of Choline from the grain boundaries. STEM analysis confirms the re-appearance of the stacking faults and SIMS and EDX confirm the removal of chlorine from the grain boundaries. This directly corresponds to a lowering in cell efficiency. The study provides further evidence that CdCl2 diffusion and certain microstructural defects directly affect the performance of cadmium telluride photovoltaic devices.