Synthesis and growth twinning of γ-Al2O3nanowires by simple evaporation of Al–Si alloy powder

Abstract

In this study, single-crystalline γ-Al₂O₃ nanowires were synthesized by simple evaporation of Al–Si alloy source powder at 1070 °C under different working pressures. The structures and growth mechanisms of the nanowires were examined. Under a low working pressure of 0.5 torr, uniform nanowires with a catalyst particle were synthesized by a vapor–liquid–solid mechanism and grew along a [2-20] direction. Twinning occurred parallel to nanowire growth direction and a twin angle of 15.5°/164.5° was identified. As the pressure increased, zigzag nanowires without a catalyst grew along a [−1−11] direction alternatively via a vapor–solid route. Twinning also formed with an angle of 15.5°/164.5°. Perpendicular twinning planes to the growth direction induced the deflected feature of the nanowires.