Temperature-dependent study of n-ZnO/p-GaN diodes

This work investigates the temperature dependence of the current-voltage (I- V) characteristics of n-ZnO/p-GaN junction diodes. The n-ZnO films were deposited on top of the p-GaN by dc sputtering with subsequent annealings at 500, 600, 700, and 800 °C for 60 s. The Hall measurement and the x-ray diffraction pattern are measured to study the n-ZnO films. The temperature sensitivity coefficients of the I-V characterizations are obtained by different substrate temperatures (25, 50, 100, and 150 °C) and the extracted values are 2.10, 1.93, 3.22, and 1.36 mV/ °C in the forward bias and 8.7, 8.0, 4.6, and 2.3 mV/°C in the reverse bias, respectively. The fabricated n-ZnO/p-GaN diode with ZnO annealing temperatures at 800 °C demonstrates the lowest temperature dependence.