The properties of ZnO films grown by molecular-beam epitaxy are reported. The primary focus was on understanding the origin of deep-level luminescence. A shift in deep-level emission from green to yellow is observed with reduced Zn pressure during the growth. Photoluminescence and Hall measurements were employed to study correlations between deep-level/near-band-edge emission and carrier density. With these results, we suggest that the green emission is related to donor-deep acceptor (Zn vacancy VZn−) and the yellow to donor-deep acceptor (oxygen vacancy, Oi−).

Origin of green luminescence in ZnO thin film grown by molecular-beam epitaxy

https://doc.rero.ch/record/9673/files/Fa_S._-_Low_pressure_chemical_vapour_deposition_of_ZnO_20080815.pdf

Low pressure chemical vapour deposition of ZnO layers for thin-film solar cells: temperature-induced morphological changes

This work reports the H2S gas-sensing properties of ZnO nanorod bundles and an investigation of their gas sensing mechanism. A one-dimensional ZnO nanostructure was synthesized using the hydrothermal method; scanning electron microscopy (SEM); and X-ray diffraction (XRD) spectra confirmed that the structures were crystalline ZnO of hexagonal structure. A furnace-type gas sensing system was used to characterize the nanorod bundles’ sensing properties in air containing dilute H2S gas (50 ppm) at sensing temperatures Ts ≤ 500 °C. The response of ZnO nanorod-bundle sensors to H2S gas increased with Ts; this trend may be due to chemical reaction of nanorods with gas molecules. X-ray photoelectron spectroscopy results indicated that the sensing mechanism of the ZnO nanorod-bundle sensor was explained by both the well-known surface reaction between H2S and adsorbed oxygen on ZnO, and the formation of zinc−sulfur bonding in ZnO nanorods, which becomes a dominant sensing mechanism at high Ts above 300 °C.

M Kamidaira

Papers

ZnO thin films prepared by remote plasma-enhanced CVD method