Near-room temperature synthesis of Zn²⁺-doped γ-Ga₂O₃ nanoparticles via direct oxidation of Zn–Ga alloy by ultrasound

Abstract

This study used ultrasound irradiation to fabricate Zn 2+ -doped £-Ga 2 O 3 nanoparticles (NPs) from ZnGa alloy at near-room temperature (60 °C). The Zn 2+ -doped £-Ga 2 O 3 NPs were obtained at 60 °C after two steps of ultrasound irradiation (miniaturization and oxidation of ZnGa alloy). The specific surface area of Zn 2+ -doped £-Ga 2 O 3 NPs with a zinc content of 4 at.% was 90.4 m 2 /g. The oxidation behavior of ZnGa liquid alloy significantly differed from that of liquid Ga. X-ray photoelectron spectroscopy spectrum and lattice constant of Zn 2+ -doped £-Ga 2 O 3 confirmed Zn 2+ -doping into the £-Ga 2 O 3 crystal structure. By annealing at 900 °C, the obtained Zn 2+ -doped £-Ga 2 O 3 did not transform to Zn 2+ -doped ¢-Ga 2 O 3 but to the mixed phase of ¢-Ga 2 O 3 and ZnGa 2 O 4 . The results indicate that Zn 2+ cations, with larger ionic radii than Ga 3+ cations, are more difficult to be introduced into the ¢-Ga 2 O 3 crystal lattice. Thus, this ultrasound process can potentially synthesize various metal cations-doped £-Ga 2 O 3 NPs without using high temperatures and pressures.

Enhancement of crystalline quality and solar-blind photodetection characteristics of ε-Ga2O3 films by introducing Zn impurity

“…Owing to the similar ionic radii of Ga 3+ (0.062 nm) and Zn 2+ (0.074 nm), Zn alloying/doping has been widely used to improve the performance of Ga 2 O 3 , 31–35 and some results show that the oxygen vacancy defects can be significantly suppressed by introducing Zn into Ga 2 O 3 . 36,37 However, most previously studies have focused on the most stable β-Ga 2 O 3 , while relatively few studies have been conducted on other metastable phases; 38,39 in particular, Zn-doped ε-Ga 2 O 3 has still not been reported. In this work, oxygen-vacancy-free ε-Ga 2 O 3 film was epitaxially grown on a c -sapphire substrate using metal organic chemical vapor deposition (MOCVD) by introducing 6.34 at% Zn and face-to-face post-annealing in oxygen.…”