Decrease in crystallization temperature of β-Ga2O3 in nanowire structure

Abstract

We have found that Ga2O3 nanowires (NWs) become β-type at about 600 °C, which is much lower than 900 °C known for bulk and thin films. The raw NWs were chemically synthesized at 70 °C in a flask. When the NWs were heat-treated at 400 °C or lower, ε-Ga2O3 was formed, and when heat-treated at 600 °C or higher, β-Ga2O3 was formed. The phase transition from ε-type to β-type occurred at around 500 °C during the temperature rise. Chemical synthesis and heat treatment was found to be low-cost methods for producing β-Ga2O3 NWs, which is expected to be applied to high-speed transistors and high-efficiency sensors.