Crystal Phase Control of Self-Catalyzed GaAs Nanowires on Native Oxide Si Substrates by the V/III Flux Ratio

Semiconducting nanowires (NWs) have shown great promise for the development of novel optoelectronic devices. However, the fabrication of uniform GaAs NWs with a small diameter is challenging due to the coexistence of wurtzite and zinc blende (ZB) crystal phases, which has degraded their optical and electrical properties. In this article, GaAs NWs have been grown on the Si substrate with a natural oxide layer. Based on investigations of structural and optical properties, it is confirmed that the shape, crystal phase, and aspect ratio of GaAs NWs can be effectively controlled only by the V/III flux ratio during the growth process. The results demonstrate the successful fabrication of quasi-pure ZB GaAs NWs with a uniform diameter and high aspect ratio. The findings may positively impact the regulation of crystal phases and the development of structural band gap engineering for other III–V NWs and contribute to the device performance improvement based on NWs with a high aspect ratio. The paper has reported the crystal phase control of GaAs NWs grown on native oxide silicon substrates in molecular beam epitaxy by changing the V/III flux ratio.