Electroluminescence of ZnO nanocrystal in sputtered ZnO-SiO₂ nanocomposite light-emitting devices

We have demonstrated the electroluminescence (EL) of Ga:ZnO/i-ZnO-SiO ₂ nanocomposite/p-GaN n-i-p heterostructure light-emitting devices (LEDs). ZnO nano-clusters with sizes distributing from 2 to 7nm were found inside the co-sputtered i-ZnO-SiO₂ nanocomposite layer under the observation of high-resolution transparent electron microscope. A clear UV EL at 376 nm from i-ZnO-SiO₂ nanocomposite in these p-i-n heterostructure LEDs was observed under the forward current of 9 mA. The EL emission peak at 376 and 427nm of the Ga:ZnO/i-ZnO-SiO₂ nanocomposite/p-GaN n-i-p heterostructure LEDs were attributed to the radiative recombination from the ZnO clusters and the Mg acceptor levels in the p-GaN layer, respectively.