“Local Photocarrier Dynamics in CdTe Solar Cells Under Optical and Electron Beam Excitations”, H. P. Yoon, P. M. Haney, Y. Yoon, S. An, J. I. Basham, and N. B. Zhitenev, 42th IEEE Photovoltaic Specialists Conference, p. 1, 2015. (DOI: 10.1109/PVSC.2015.7356020)
1. Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland, 20899, USA.
2. Maryland Nanocenter, University of Maryland, College Park, Maryland, 20742, USA
ABSTRACT. We compare local carrier dynamics in n-CdS / p-CdTe solar cells, where the electron-hole pairs are generated by either near-field optical illumination or highly focused electron beam excitation. An ion beam milling process was used to prepare a smooth surface of cross-sectional devices. The spatially resolved photocurrent images confirm high carrier collection efficiency at grain boundaries. An analytical model was used to extract material parameters at the level of single grains. We find that the minority carrier diffusion lengths extracted from both local measurement techniques are in excellent agreement, but are smaller than the values determined from macro-scale measurements.