Low-Temperature As-Doped In₂O₃ Nanowires for Room Temperature NO₂ Gas Sensing

Recently, In2O3 nanowires (NWs) have been extensively explored for high performance electronics and optoelectronics; meanwhile, it is still challenging to synthesize single-crystalline In2O3 NWs at low temperature using complementary metal oxide semiconductor (CMOS) technology compatible catalysts. In this study, single-crystalline As-doped In2O3 NWs are synthesized by chemical vapor deposition (CVD), using InAs as the In source and Cu2O nanocubes with uniform morphology as the CMOS compatible catalyst seeds. The growth temperature is optimized to be ∼600 °C, far lower than the melting point (827 °C) of the Cu3As seeds inferring the vapor–solid–solid (VSS) growth mechanism. The obtained NWs have a narrow diameter distribution of 72 ± 18 nm along the entire NW length and a preferential growth direction of ⟨100⟩ attributable to the epitaxy relationship with the Cu3As ⟨110⟩ plane. NO2 gas sensing measurements show the diameter dependent response, attributable to the increased surface to volume ratio of small diameter NWs. All of these have shown that the outstanding potency of such NWs is based on Cu2O nanocubes for diverse technological applications.