Study of iron-catalysed growth of β-Ga2O3 nanowires and their detailed characterization using TEM, Raman and cathodoluminescence techniques

Abstract

In this paper, we demonstrate a new catalyst (Fe) to grow single crystalline beta-gallium oxide (β-Ga2O3) nanowires (NWs) via the vapour–liquid–solid mechanism using the chemical vapour deposition technique. The structural studies of these NWs showed the highly crystalline monoclinic phase of Ga2O3. This was confirmed by detailed scanning transmission electron microscope investigations demonstrating the NW to be single crystalline β-Ga2O3, growing along the normal of the plane. We also compared Raman and cathodoluminescence (CL) properties of the as-grown β-Ga2O3 NWs with a bulk Ga2O3 single crystal grown by the Czochralski method. It was observed that Raman peak positions of a single β-Ga2O3 NW had a red frequency shift of about 0.3–1.4 cm−1 as compared to a bulk Ga2O3 single crystal, which was in fact quite small. In addition, the CL measurements of β-Ga2O3 NWs and the bulk Ga2O3 single crystal exhibited similar spectra, having a strong broad UV–blue emission band and a weak red emission band. Moreover, the structural, morphological and optical properties of Fe-catalysed β-Ga2O3 NWs were comparable to those of Au-catalysed β-Ga2O3 NWs.