Numerical simulation of the I-V characteristics of heterojunctions including thermionic emission mechanism

The effects of temperature, Al mole fraction, and doping on the I-V characteristics of abrupt GaAs/AlGaAs heterojunctions are studied by numerically solving the basic semiconductor equations. Numerical models based on drift-diffusion with and without inclusion of thermionic emission current at the heterointerface are used and their results are compared. The simulation shows that neglecting the thermionic emission will overestimate the current, especially, at lower temperatures, at higher mole fraction, or for n-N structures. Under high injection, as temperature increases, current becomes limited mainly by the series resistance. The asymmetry of doping level its found to affect significantly the transport process at lower temperatures only