VLS Growth of Position-controlled InP Nanowires and Formation of Radial Heterostructures on Mask-patterned InP Substrates

Position-controlled InP nanowires (NWs) with separations of 10–100 μm were grown by the vapor-liquid-solid (VLS) method using Au-deposited SiO 2 -mask-patterned InP substrates. Excess indium species diffused from the large mask region formed plural tilted NW-like structures from single openings in addition to the vertical VLS NWs formed by Au catalyst. The introduction of HCl gas during the NW growth was found to efficiently suppress the tilted NW-like structures. Vertical InP NWs without anomalous growth were successfully formed by controlling the HCl flow rate. Moreover, single InP/InAsP/InP quantum wells (QWs) with wurtzite crystal phase structure were epitaxially grown on the sidewall of the position-controlled InP NWs, and two-dimensional arrayed patterns of photoluminescence (PL) coming from the radial QWs were clearly observed in the 1.3-μm wavelength region at room temperature.