The optical band gap of ZnO thin films deposited on fused quartz by metal-organic chemical-vapor deposition was studied. The optical band gap of as-grown ZnO blueshifted from 3.13 to 4.06 eV as the growth temperature decreased from 500 to 200°C. After annealing, the optical band gap shifted back to the single-crystal value. All the ZnO thin films studied show strong band-edge photoluminescence. X-ray diffraction measurements showed that samples deposited at low temperatures ͑Ͻ450°C͒ consisted of amorphous and crystalline phases. The redshift of the optical band gap back to the original position after annealing was strong evidence that the blueshift was due to an amorphous phase. The unshifted photoluminescence spectra indicated that the luminescence was due to the crystalline phase of ZnO, which was in the form of nanocrystals embedded in the amorphous phase.

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Self-organized zinc oxide (ZnO) nanofiber network with six-fold symmetry was fabricated on ZnO-buffered (0001) sapphire substrate with patterned gold catalyst by vapor-phase transport method. From the ZnO buffer layer, hexagonal ZnO nanorods with identical in-plane structure grew epitaxially along [0001] orientation to form vertical stems. The nanofiber branches grew horizontally from six side-surfaces of the vertical stem along [011¯0] and other equivalent directions. The aligned network structure constructed a waveguide array with optical gain. Ultraviolet amplified spontaneous emission was observed along the side-branching nanofibers when the aligned ZnO network was excited by a frequency-tripled Nd:YAG laser.

Field-free spin-orbit torque switching of a perpendicular ferromagnet with Dzyaloshinskii-Moriya interaction. Applied Physics Letters, 114(2), article no. 022401. For guidance on citations see FAQs.

Structural and optical properties of zinc oxide film using RF-sputtering technique AIP Conf. Proc. 1502, 538 (2012); 10.1063/1.4769172Compositional study of vacuum annealed Al doped ZnO thin films obtained by RF magnetron sputtering Second and third order nonlinear optical properties of microrod ZnO films deposited on sapphire substrates by thermal oxidation of metallic zincPostgrowth annealing was carried out on ZnO thin films grown by metal-organic chemical-vapor deposition. It was found from the scanning electron microscopy and atomic force microscopy measurements that the morphology of the thin films changed drastically after annealing. The as-grown thin films consist of fine nanoscale-sized sheets with random orientation. Upon annealing at 800°C, the ZnO nanosheets changed to three-dimensional nanoneedles. The different types of the mass transport mechanisms are discussed and correlated with the experimental results. A coarsening kinetics developed by Lifshitz and Slyozov ͓J. Phys. Chem. Solids 19, 35 ͑1961͔͒ and Wagner ͓Z. Elektrochem. 65, 581 ͑1961͔͒ was used to estimate the activation energy of the coarsening process. The activation energy of the Ostwald ripening in ZnO films was estimated in the first attempt, and the value is at around 1.33 eV. Hall effect and photoluminescence measurements were carried out to investigate the effect of coarsening on electrical and optical properties of the ZnO thin films.

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Poly(p-phenylene vinylene)-based polymer light-emitting devices using different thicknesses of tetrahedral amorphous carbon ultrathin films between indium tin oxide and polyethylenedioxythiophene hole transporting layer have been fabricated. The device with a 0.5nm tetrahedral amorphous carbon (ta-C) layer has the highest luminance and current efficiency compared to that of other devices. The current efficiency of a standard device without a ta-C layer is 1.1cd∕A at 5V, however, the current efficiency of a device with a ta-C layer thickness of 0.5nm is 2.7cd∕A; the current efficiency is improved about 2.5 times compared to the standard device. The improvement of the efficiency is due to blocking the hole injection from anode and balancing the hole and electron current. The lifetime of a device with a ta-C layer is significantly much longer than the standard device, and the device with a 0.5nm ta-C layer has the longest lifetime.