Introducing CuO films as hole transport materials to GaN-based heterojunction LED

The basic structure of p-CuO/n-GaN heterojunction light emitting diodes (LEDs) were demonstrated using CuO films as the hole transport material by frequency reactive magnetron sputtering. The current-voltage (I-V) characteristics of the diodes revealed a typical p-n diode nature with a turn-on voltage of 2.0 V and leakage current of 10(-6) A. The electroluminescence spectra from the p-CuO/n-GaN diodes at different forward bias voltages exhibited blue-light emissions peaked around 446 nm, which was corresponding to the radiative combination between electrons and holes in the depletion region. The blue-light emission was strong enough to be clearly seen by the naked eye at the forward bias voltage of 8 V. Moreover, the working mechanism of the blue emission was preliminary discussed in terms of the energy band diagram of the diode.