Growth of GaAs nanowires on Si substrates using a molecular beam epitaxy

Au-catalyzed GaAs nanowires were grown on Si substrates by vapor-liquid-solid growth method using a molecular beam epitaxy (MBE). The MBE growth could produce controlled crystalline orientation and uniform diameter along the wire axis of the GaAs nanowires by adjusting growth conditions including growth temperature and V/III flux ratio. Growths of GaAs < 001 > as well as GaAs < 111 > nanowires were observed by transmission electron microscopy and scanning electron microscopy. Epitaxially grown GaAs < 111 > nanowires on a Si(111) substrate were verified through x-ray diffraction out-of-plane 2 theta/omega-scans. A strong room-temperature photoluminescence (PL) was observed from the epitaxially grown GaAs < 111 > nanowires on a Si(100) substrate. Results of low-temperature (10 K) PL measurements and current-sensing atomic force microscopy indicated that the GaAs nanowires; on a Si substrate were unintentionally doped with Si.