Vapor-liquid-solid growth and characterization of al-catalyzed Si nanowires

Alternative metal catalysts are of interest for the vapor-liquid-solid (VLS) growth of silicon nanowires (Si NWs) both from a fundamental growth perspective and as a pathway to control the electrical properties. Gold is the most commonly used metal catalyst, however, gold forms deep level electronic states within the bandgap of Si that are undesirable, particularly for photovoltaic devices that are dependent on minority carrier transport. Aluminum is of particular interest since it forms a liquid eutectic phase with Si at ~577°C and can serve as both a catalyst for nanowire growth and a source for p-type doping. However, Si NWs synthesis using Al is challenging due to the reactivity of Al with ambient O₂ and H₂O, which results in the formation of a surface oxide layer that impedes nanowire growth.