Transport Across Silicon Grain Boundaries

Abstract

ABSTRACTBy comparison of the capacitance and the conductivity of p–type Si bicrystals, we show quantitatively that current transport occurs through thermionic emission of holes across the potential barrier, which is caused by charged donors in the grain boundary. Starting from this finding, we propose a simple model which allows for the first time a spectroscopic determination of the grain boundary density of states from photocapacitance data. Results indicate the presence of band tails and additional mid-gap states.