Highly directional InAs nanowires grown on Si(111) by selective-area molecular-beam epitaxy

Effects of growth conditions including V/III ratio, initial treatment and hole diameter on the selective-area MBE growth of InAs nanowires (NW) on patterned Si (111) substrates are investigated. High V/III ratio favors the axial growth of the NWs. Results from vertical yield study suggests that (111)B is an inherent preferential domain when growth InAs on non-polar (111)Si. The preference is independent of the treatments. However, As illumination before the growth could convert the (111)Si to (111)A InAs and thus decreases the vertical yield. So far, we have successfully achieved a vertical yield over 70%.