Photoluminescence property of Cr-doped β-Ga2O3 nanorods synthesized by a hydrothermal method

Abstract

Cr-Doped β-Ga₂O₃ nanorods were synthesized by a hydrothermal method and were characterized in detail so as to analyze the effects of Cr³⁺ doping on their crystalline quality and photoluminescence property. X-ray photoelectron spectroscopy proves the successful doping of Cr³⁺ ions in Ga₂O₃ by the hydrothermal method; however, no significant effect of Cr³⁺ doping on the crystal structures of the GaOOH precursor and the β-Ga₂O₃ product was observed via X-ray diffraction. The uniform distribution of the doped chromium ions in the gallium oxide product can be seen in EDS and XPS images. Moreover, for Cr³⁺-doped Ga₂O₃, infrared absorption peaks located at 455.14 cm⁻¹ and 667.28 cm⁻¹ correspond to the Ga–O bond contraction vibrations of regular octahedral (GaO₆) and regular tetrahedron (GaO₄), respectively. A broad emission in the range of 650–800 nm was observed, which was due to the ⁴T₂–⁴A₂ energy level transition of chromium ions. No emission peak was found in the range of 450–700 nm for the Ga₂O₃ sample without Cr³⁺ doping. Further, the near-infrared luminescence mechanism of β-Ga₂O₃:Cr³⁺ is discussed briefly.