A UV‐light‐emitting homojunction ZnO LED is grown by radiofrequency sputtering at high temperature, improving the structural, electrical, and optical properties of the n‐ and p‐type ZnO layers. The figure shows a comparison of the electroluminescence spectra of A) a p–n homojunction ZnO LED and B) a ZnO LED with Mg0.1Zn0.9O layers used as energy barrier layers. Such materials are of interest for their potential use in long‐lifetime solid‐state lighting, high‐density information storage, secure communication, and chemical/biological‐agent monitoring.

Disorder induced semiconductor to metal transition and modifications of grain boundaries in nanocrystalline zinc oxide thin film J. Appl. Phys. 112, 073101 (2012) Robust low resistivity p-type ZnO:Na films after ultraviolet illumination: The elimination of grain boundaries Appl. Phys. Lett. 101, 122109 (2012) P-type ZnO thin films achieved by N+ ion implantation through dynamic annealing process Appl. Phys. Lett. 101, 112101 (2012) Controlling the resistivity gradient in aluminum-doped zinc oxide grown by plasma-enhanced chemical vapor deposition J. Appl. Phys. 112, 043708 (2012) Schottky solar cells based on CsSnI3 thin-films Appl.

ZnO thin films were epitaxially grown on α-Al2O3 (0001) substrate by radio-frequency (rf) magnetron sputtering. Among the ZnO films deposited at 550 °C, the film deposited at 80 W has the narrowest full width half maximum (FWHM) of x-ray diffraction (XRD) θ-rocking curve, 0.16°, indicating a highly c-axis oriented columnar structure. The FWHM of XRD θ-rocking curve of the ZnO film deposited at 120 W and 600 °C was 0.13° with a minimum channeling yield, 4%–5%. In photoluminescence (PL) measurement, only the sharp near band edge emission was observed at room temperature (RT). The FWHM of PL peak was decreased from 133 to 89 meV as rf power increased from 80 to 120 W at 550 °C, and that of film deposited at 120 W and 600 °C showed 76 meV which is lower value than any other ever reported. These PL results were somewhat opposite to that of XRD. From transmission electron microscopy analysis, grain size and defects were found to affect the PL properties. In this study, the PL property of undoped ZnO thin films is discussed in terms of the crystalline structure and the size of grain.

The dry etching characteristics of ZnO using an inductively couple plasma (ICP) have been investigated, for the first time, as functions of plasma chemistry, radio frequency (rf) table power, and ICP power. The CH 4 /H 2 etchant gases resulted in the highest etch rate of ZnO, suggesting that the etching of Zn in ZnO largely involves a process in which a volatile metallorganic zinc compound, such as Zn(CH 3) y is formed. The etch rate was increased with increasing rf table power, and the highest etch rate of 2000 Å/min was achieved at an rf table power of 200 W (dc bias: Ϫ80 V). As the ICP power was increased, the etch rate also increased, which suggests that the plasma density is also an important factor in this process. Furthermore, it was observed that hydrogen-containing plasma etching enhances the band-edge photoluminescence of the ZnO film.