Structural and Luminescence Properties of Ga₂O₃:Zn Micro‐ and Nanostructures

Abstract

High quality Zn‐doped monoclinic gallium oxide micro‐ and nanostructures are obtained by a thermal treatment based on vapor–solid (VS) growth mechanism. Nanowires and ribbons are formed, the latter being the more abundant. The microstructural features are assessed by micro‐Raman and transmission electron microscopy revealing their crystal structure properties, such as the [‐110] growth direction for ribbons and being single crystals. In particular, a strong‐scattered light polarization dependence is reflected in the detected Raman modes. Luminescence of both Zn doped and undoped Ga 2 O 3 samples is thoroughly studied by several techniques, exciting light with electrons or photons. Cathodoluminescence (CL) at a wide temperature range reveals that a band centered at around 2.7 eV, assigned to Zn doping in monoclinic Ga 2 O 3 , is thermally activated at temperatures above 200 K and dominates at room temperature. Besides, the characteristic bands at 3.4 and 3.0 eV of undoped Ga 2 O 3 are obtained as well but with less relative intensity. Photoluminescence (PL) analysis at room temperature shows a similar set of bands, but slightly redshifted with respect to CL. Their relative intensities are strongly dependent on the excitation conditions and their time decays are studied by time‐resolved PL (TRPL).