Analysis of temperature dependent electrical characteristics of Au/n-GaAs/GaAs structures in a wide temperature range

The temperature dependence of some electrical parameters of Au/n-GaAs/GaAs structures obtained from the forward bias current-voltage (I-V) and reverse bias capacitance-voltage (C-V) characteristics is studied in the temperature range of 79-400 K. The forward bias current I is found to be proportional to Io(T)exp(AV), where A is the slope of Ln(I)-V curves and almost independent of the voltage and temperature, and Io(T) is relatively a weak function of temperature. The semi-logarithmic Ln(I)-V characteristics based on the thermionic emission (TE) mechanism showed a decrease in the ideality factor (n) and an increase in the zero-bias barrier height (ΦBo) with increasing temperature. These behaviors don't obey the pure thermionic emission (TE) theory. However, the barrier height ΦB(C-V) determined from the C−2-V plot at high frequency decreased linearly with the temperature. Analysis of the data indicated that the predominant current conduction mechanism of our sample was a trap-assisted multistep tunneling rather than the other mechanisms.