Inter-granular electrical transport in polycrystalline semiconductors via tunneling mechanism

Current-voltage (I-V) characteristics of charge transport across barriers between grain boundaries of a polycrystalline semiconductor was computed numerically using the time-dependent Schrodinger equation for barriers of different widths and heights. It is shown that the I-V characteristics follow a power low above a certain breakdown voltage V_s, with an exponent that increases with increasing barrier width and/or height. The I-V characteristics were also found to have a wavy behavior that was attributed to quantum mechanical interference effects. The effect of doping level and temperature were also considered. V_s is found to increase with increasing barrier width and/or height; however, V_s is found to be independent of doping level and temperature.