ABSTRACT
Zinc oxide (ZnO) has attracted considerable attention as a promising material for ultraviolet photonic devices such as light-emitting diodes and lasers. Atomic layer deposition (ALD) is another noteworthy method of growing high-quality ZnO thin films. ALD is a thin-film deposition technique for preparing high-quality oxides with atomic-layer accuracy. Among various substrates on which ZnO thin films were deposited, glass substrates have been extensively used due to their high transparency and low costs. The electrons and holes may accumulate in ZnO and Gallium nitride near the interface, respectively, due to the wide bandgap energy of the interfacial layer. Electrons make the transition to the deep-level states, producing the light emission around 722 nm under low injection current. High-quality ZnO thin films were deposited on commercially available semi-insulating GaAs substrates by the ALD technique. Highly oriented ZnO thin films accompanied by stimulated emission have been prepared by ALD on amorphous glass substrates.
