Current-voltage dependencies of heterogeneous semiconductor systems

Abstract

Computed current-voltage (J–V) dependencies of heterogeneous (powder) semiconductor systems reveal an anomalous dependence between the constant-voltage current J and the uncompensated donor (acceptor) concentration N. Over a range of N( N 1 < n < N 2) of approximately one decade, J decreases by as much as four decades with increasing N. For N > N 2, the grain Schottky barrier thickness d is less than the grain half-width l/2, the grain surface potential V s is almost independent of N and the J–V dependence is superlinear. For N 1 < N < N 2, d > l/2, V s decreases linearly with N, J increases strongly with decreasing N and the J–V dependence is superlinear. For N < N 1, d > l/2. V s ⪝ V th ( = kT/q) and J ∝ NV. The phenomenon is used to account for some observed J–V dependencies with column II-chalcogenide and ZnO powder semiconductor systems (electro-optic displays, electrophotographic receptors and heterogeneous catalysts).