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 degrees 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 degrees C) and the extracted values are 2.10, 1.93, 3.22, and 1.36 mV/degrees C in the forward bias and 8.7, 8.0, 4.6, and 2.3 mV/degrees C in the reverse bias, respectively. The fabricated n-ZnO/p-GaN diode with ZnO annealing temperatures at 800 degrees C demonstrates the lowest temperature dependence. (c) 2007 American Institute of Physics.