Nonlinear current-voltage characteristics in MeBi2O3Me structure

Abstract

The current‐voltage (I–U) characteristics, both under illumination from the photosensitivity region and the dark I–U characteristics, are studied in MeBi2O3Me structures at different temperatures versus sample thickness and the configuration and material of electrodes. In the I–U characteristics four distinct regions are observed: ohmic I ∼ U, superlinear I ∼ Un > 1, the region of reverse bend where the degree of nonlinearity decreases and approximates the value of n = 1, and the second superlinear region I ∼ Un > 1. With increasing temperature of the samples the degree of nonlinearity decreases, the voltage in the beginning of the superlinear region increases slightly. In MeBi2O3Me structures the nonlinear I–U characteristics are explained in terms of a semiconductor model with intergrain barriers. The height of intergrain barriers (φ0 = (0.19 to 0.24) eV) and the average size of crystallites (h = (0.25 to 0.35) μm) for δ‐Bi2O3 films are determined from the experimental I–U characteristics.