A comparative study of β-Ga2O3 nanowires grown on different substrates using CVD technique

Highlights: • The effect of different substrates on the structural, morphologies and optical properties of β-Ga2O3 NWs is investigated. • The CL and Raman spectra of β-Ga2O3 NWs grown on different substrates show similar features. • The estimated band gaps are ∼4.76 eV, ∼4.82 eV, and ∼4.83 eV for β-Ga2O3 NWs grown on sapphire, GaN/sapphire and Si, respectively. -- Abstract: A comparative study of beta gallium oxide (β-Ga2O3) nanowires (NWs) grown on different substrates such as silicon (Si), sapphire, and GaN/sapphire has been reported. Field emission scanning electron microscopy (FESEM) results revealed that the β-Ga2O3 NWs grown on GaN/sapphire substrate were comparatively more aligned than grown on other substrates. The diameter of the NWs varied from 150 to 400 nm, and their length ranging up to tens of micrometers. X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) showed the single crystalline monoclinic nature of NWs. The Raman spectra acquired from three samples revealed similar features consisting of two active modes such as mid and high frequency. However, low frequency mode was absent in our results. The cathodoluminescence (CL) spectra of β-Ga2O3 NWs on different substrates showed a strong broad UV-blue emission band and a weak red emission band in all the samples. Hence, the morphologies and structural properties of the β-Ga2O3 NWs grown on three substrates showed some observable changes, while their optical properties were quite similar