Effect of high-energy electron beam irradiation on the properties of ZnO thin films prepared by magnetron sputtering A comparative analysis of deep level emission in ZnO layers deposited by various methods ZnO nanowire NW growth mechanism was investigated in a nonvapor and noncatalytic approach for the controlled NW synthesis in a second time scale. The experimental results showed what ZnO NW growth was determined by migration of zinc interstitials and vacancies in a ZnO layer, which should be also considered in other synthesis techniques and mechanisms. The mechanism of the ZnO NW growth was explained as due to the advantageous diffusion through grain boundaries in ZnO layer and crystal defects in NWs. Additionally, on the basis of photoluminescence measurements, a feasible application of as-produced wires for optoelectronic devices was demonstrated.

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We report enhanced exciton-phonon interactions in the photoluminescence (PL) of ZnO nanopencils compared with ZnO nanorods grown on ZnO/Si templates by thermal evaporation. Although the low temperature (<100 K) PL spectra of ZnO nanorods and nanopencils were dominated by the strong donor-bound exciton, the PL spectra at elevated temperatures (>100 K) showed dominant contributions from the free exciton emissions and phonon-replicas of free excitons for nanorods and nanopencils, respectively. This discrepancy in the behaviors of excitonic emissions of the ZnO nanorods and nanopencils was related to surface defects causing different strengths of exciton-phonon coupling. The different excitonic emissions of the nanorods and nanopencils revealed a 52 meV redshift in the room temperature PL of nanopencils.

We report catalyst-free growth of one-dimensional Ga-doped ZnO nanorod arrays on (001) Si substrate with a thin buffer layer by magnetron sputtering. The diameter and length of the nanorods are in the range of 90-144 nm and about 1.38 µm, with an aspect ratio nearly 12:1 and deviation angle ( 6°between the [0001] ZnO direction and substrate normal. The photoluminescence spectra of the nanorods are dominated by intense near band-edge emission with weak deep-level emission. The good field emission properties of the nanorod arrays with turn-on field of 2.9 V/µm and enhancement factor of 2027 demonstrate the perfect single-crystalline growth of ZnO:Ga nanorods with similar vertical alignment.

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