Recommended Citation Long, Qi, "Drift Mobility Measurements and Electrical Characterization in Thin Film Cadmium Telluride Solar Cells " (2015).

Thin film CdTe solar cells are leading the production in the thin film photovoltaic industry for the recent few years. The electric properties and mechanism for fabrication of high efficiency solar cells are still not well established. In this thesis, I’ll report electron and hole drift mobilities measurements in thin film CdTe solar cells based on two characterization methods: time-of-flight and photocapacitance. For a deposition process similar to that used for high-efficiency cells, the electron drift mobilities are in the range 10-1 – 100 cm2/Vs, and holes are in the range 100 – 101 cm2/Vs. The electron drift mobilities are three orders of magnitude smaller than those measured in single crystal CdTe, the hole mobilities are about ten times smaller. Cells were examined before and after a vapor phase treatment with CdCl2; treatment had little effect on the hole drift mobility, but decreased the electron mobility. The electron mobility shows an interesting inverse correlation with the open-circuit voltage for the CdTe coupons with and without the CdCl2 treatment. We speculate that this correlation is due to the diffusion limited recombination. We also discuss the mechanisms reducing th