Optical and structural properties of InP nanowires grown under vapor-liquid-solid mechanism by metal organic vapor phase epitaxy

Metal organic vapor phase epitaxial growth of surface mounted and vertically aligned InP nanowires under the vapor-liquid-solid mechanism is being reported in this paper. Two types of the nanowires were grown by using the suspended Au nanoparticles of 10 and 20 nm nominal diameters as the catalyst and their structural and optical properties were compared. Scanning electron microscopy showed the growth of isolated, of uniform cross section along the length and the large number of nanowires per unit area in range of 7-10×10⁹ cm^-2 for both the Au nanoparticles used. The distribution in the diameters of the nanowires grown using the 10 and 20 nm Au nanoparticles were in the ranges of 5-110 and 5-60 nm, respectively, with the average length of 700 nm, irrespective of the type of the catalysts used. Transmission electron microscopy showed the <111> orientation of the nanowires with the presence of alternate rotational twin structures along the length. Energy dispersive X-ray analysis was carried out for elemental analysis of a single nanowire. The nanowires showed clear room temperature photoluminescence spectra with the peaks blue shifted by 25 and 32 meV due to the quantum confinement of the carriers in the nanowires grown on 10 and 20 nm Au nanoparticles, respectively. The successful growth of these nanowires will help in realizing the wafer scale fabrication and integration of new electro-optic devices under the bottom-up approach.