Temperature dependence of current-voltage (I-V) characteristics of Pt/Au Schottky contacts on n-type GaN

The current-voltage (I-V) characteristics of Pt/Au Schottky contact on n-type GaN were measured in wide temperature range 85-405 K. The IN curves is fitted by the equation based on thermionic emission theory, but the zero-bias barrier height (phi(BO)) decreases and the ideality factor (n) increases with decreasing temperature. The zero-bias barrier height (phi(BO)), ideality factor (n) and series resistance (R-s) values are seen to be strongly temperature dependent. It is shown that the values of series resistances (R-s) were strongly temperature dependent and decreased with increasing temperature, and values were found in the range 1493 Omega at 85 K- 94 Omega at 405 K. The flat-band barrier height phi(BF)(T=0 K) and temperature coefficient (alpha) are evaluated to be 0.71 eV and 1.91 x 10(-3) eV/K by the current-voltage method. The calculated value of Richardson constant is 14.6 Acm(-2)K(-2) from temperature dependent I-V studies, which is lower than the known value. It can be concluded that the temperature dependence of I-V characteristics of the Pt/Au/n-GaN Schottky diode can be successfully explained on the basis of thermionic emission (TE) mechanism.