Growth of β‐gallium oxide films and nanostructures by atmospheric‐ pressure CVD using gallium and water as source materials

Abstract

Abstract Films and nanostructures of β‐Ga 2 O 3 were successfully grown by atmospheric‐pressure CVD (AP‐CVD) using metal Ga and H 2 O as source materials. It was confirmed that highly (‐201) oriented polycrystalline β‐Ga 2 O 3 films can be obtained on c ‐plane sapphire ( c ‐Al 2 O 3 ) substrates by optimizing growth temperature ( T g ) and source supply ratio of H 2 O to Ga. The optical gap energy of the β‐Ga 2 O 3 film with a relatively flat surface was estimated to be ∼4.9 eV. Photoluminescence (PL) measurements for the β‐Ga 2 O 3 films revealed the existence of at least three emission bands with their peaks at ∼370 nm, ∼440 nm and ∼520 nm. Various shapes of quasi 1D nanostructures, such as nanowires (NWs), nanorods (NRs), tapered NRs and nanobelts (NBs), were obtained on the c ‐Al 2 O 3 substrates coated with the Au films by utilizing vapour‐liquid‐solid (VLS) growth mechanism. The diversity of the quasi 1D nanostructures is probably due to the contribution of vapour‐solid (VS) growth mechanism and/or the coalescence between the neighbouring Au metal particles before initiating the NW (or NR) growth. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)