Electrical properties and carrier transport mechanism in V/p-GaN Schottky diode at high temperature range.

The electrical properties and carrier transport mechanism of vanadium (V) Schottky contacts on p-type GaN have been investigated. The electrical characteristics are analyzed by using current–voltage–temperature, turn-on voltage–temperature and series resistance–temperature in the temperature range of 280–400 K. An exponential decrease in the experimental series resistance ( R S ) and increase in the ideality factor ( n ), Schottky barrier height (SBH) with decrease in the temperature is observed. The characteristic temperature ( T 0 ) resulting from the Norde’s function is compared with those from the Cheung’s functions, and it is observed that there is good agreement between the T 0 values from both methods. Experimental results reveal that the thermal coefficient ( K j ) is −1.0 mV/K at ⩾280 K. The effective SBH is determined to be 1.88 ± 0.2 eV, which is in good agreement with the theoretical value. The feasible carrier transport mechanism of V/p-GaN Schottky diode is discussed based on the thermally decreased energy band gap of p-type GaN layers, thermally increased deep-level acceptor and increased further activated shallow-level acceptor. [ABSTRACT FROM AUTHOR]