Onset of diffusion-drift emission regime and the transition from exponential to linear current-voltage characteristic of triangular barrier semiconductor structures

Abstract

Using a very simple physical model of charge motion in triangular barrier structure as a Brownian motion over a potential barrier, we show that there are essentially four regimes of operation, with increasing bias voltage, in these device structures. These are (a) the thermionic emission regime, (b) the diffusion emission regime, (c) the diffusion-drift emission regime, and (d) the linear current-voltage (I-V) characteristic, drift emission regime. The diffusion emission regime occurs only for a particular value of the applied voltage and marks the onset of diffusion-drift emission regime. This simple physical model gives excellent agreement with the experimental data, particularly under forward bias.