Study of high quality spinel zinc gallate nanowires grown using CVD and ALD techniques

Abstract

High quality single crystalline zinc gallate (ZnGa2O4) nanowires (NWs) were grown using a combination of chemical vapor deposition and atomic layer deposition techniques. Morphological, structural and optical investigations revealed the formation of Ga2O3-ZnO core-shell NWs and their conversion into ZnGa2O4 NWs after annealing via a solid state reaction. This material conversion was systematically confirmed for single NWs by various measurement techniques including scanning and transmission electron microscopy, Raman spectroscopy and voltage-dependent cathodoluminescence. Moreover, a model system based on the obtained results has been provided explaining the formation mechanism of the ZnGa2O4 NWs.

Structural Characteristics and Photoluminescence Properties of Sputter-Deposition ZnGa2O4 Thin Films on Sapphire and Si(100) Substrates

“…ZnGa 2 O 4 phosphor materials have been prepared by several methods, including radio-frequency (RF) magnetron sputtering [6], sol-gel processing [7], metal organic chemical vapor deposition (MOCVD) [8] and pulsed laser deposition [9]. However, they are mostly used to conduct synthesis of one-dimensional nanostructures (nanoparticles, nanowires and nanotubes) and are known to improve the emission characteristics of ZnGa 2 O 4 phosphor powder [10][11][12]. In fact, thin film structures are more stable and reliable than one-dimensional nanostructures and better adhere to solid surfaces in practical devices.…”

Metal β-diketoiminate precursor use in aerosol assisted chemical vapour deposition of gallium- and aluminium-doped zinc oxide

“…A shift in the peak position when doping occurs due to the change in lattice parameters that accompanies the introduction of dopant atom into the host matrix, shifting was observed when compared to the 2θ values of the undoped zinc oxide films. Firstly for the (002) peak from 34.85° to 35.00° 2θ and the (100) peak from 31.40° to 32.15° 2θ. The replacement of Zn 2+ ions with the smaller Al 3+ ions caused a shift of the (100) peak to a larger 2θ.…”

“…[31,32] A mechanism analogous to this effect has been used to synthesize spinel structures of the type AB2O4, from a range of techniques including ALD and CVD whereby layers of different materials are heated above a certain temperature. [33][34][35] It is likely that the GZO films presented herein have an amorphous layer of oxide at their surface. This can be difficult to detect in films deposited at 400 °C because Ga2O3 is amorphous at this temperature ruling out XRD analysis, furthermore the low doublet separation in the XPS for gallium implies that any number of environments can fit the single peak recorded.…”