Ultraviolet electroluminescence from ZnO-based n-i-p light-emitting diodes

The p-type ZnO films were obtained using codeposition of ZnO and LiNO ₃ sources by the vapor cooling condensation system. With an adequate postannealing temperature, the p-type conductive behaviors of the resulting ZnO films could be achieved due to the activation of Li-N dual acceptor. According to the emission energy of free electron to acceptor hole level, the acceptor binding energy of 137 meV was obtained. Furthermore, the ZnO-based n-i-p ultraviolet light-emitting diodes were deposited on sapphire substrates using the vapor cooling condensation system. A rectifying diode-like behavior and ultraviolet emission were observed from the ZnO-based n-i-p light-emitting diodes.