One-Step Preparation of Si-Doped Ultra-Long β-Ga2O3 Nanowires by Low-Pressure Chemical Vapor Deposition

Abstract

In this work, we prepared ultra-long Si-doped β-Ga2O3 nanowires on annealed Al2O3-film/Si substrate by low-pressure chemical vapor deposition (LPCVD) assisted by Au as catalyst. The length of nanowires exceeds 300 μm and diameters range from ~30 to ~100 nm in one-dimensional structures. The nanowires show good crystal quality and exhibit (201) orientation, confirmed by transmission electron microscopy and X-ray diffraction analysis. The PL spectrum obtained from these β-Ga2O3 nanowires has three obvious blue luminescence peaks at 398 nm (3.12 eV), 440 nm (2.82 eV), and 492 nm (2.51 eV). The electrical properties obtained from Si-doped β-Ga2O3 nanowires exhibit good conductivity. A metal-semiconductor-metal device is made by using Ti/Au as the electrode, and the device current reaches 200 pA at a bias voltage of 3 V. Our results show that ultra-long Si-doped β-Ga2O3 nanowires can be grown directly on the surface of Al2O3-film/Si substrates. These nanowires have a very high length-diameter ratio and good electrical properties. A possible mechanism for Si doping is also presented.