Mechanism Investigation of p-i-n ZnO-Based Light-Emitting Diodes

Using a cosputtering technique to deposit P-ZnO : AlN film and using a vapor cooling condensation system to deposit n-ZnO : In and i-ZnO films on sapphire substrates, thin-film-type ZnO-based light-emitting diodes (LEDs) were fabricated. A Nd : YAG laser with a wavelength of 413 nm is utilized to identify the defect-related emissions of p-ZnO, i-ZnO, and n-ZnO films. The characteristics of i-ZnO layer of ultraviolet (UV) emissions were analyzed using temperature-dependent photoluminescence. The mechanism of the UV electroluminescence emission peak at 3.20 eV observed from the p-i-n ZnO-based LEDs were attributed to the low deep-level defects and the radiative recombination occurred in the i-ZnO layer.