MOCVD Growth And Characterization Of Self-catalyzed InP Nanowires

Semiconductor nanowires have excellent electrical, optical, magnetic, and other properties, because one-dimensional nanomaterials show discrete energy levels, conductance quantization, ballistic transport, and coulomb blockade which called quantum confinement effect. InP is the III-V compound of semiconductors. It has direct bandgap and its bandgap energy is 1.35 eV at room-temperature. It is known for its high mobility of electrons and negative resistance effect. So InP nanowires have important application prospects in nano-optoelectronic devices.In order to integrate the superior electronic and optoelectronic properties of InP namowires with Si technology, the novel self-catalyzed InP nanowires using in situ deposited indium droplets as seeds in metal organic vapor phase epitaxy was investigated in this thesis. The InP nanowires were grown on Si (100) substrate. The morphology, growth mechanism, growth direction, crystal structure and optical properties of the nanowires were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence, and Raman scattering.The work results of this thesis include:1. The InP nanowires were grown on Si (100) substrate.The diameter, shape and length of the InP nanowires can be controlled by adjusting the growth time of In droplets, growth temperature, and V/III ratio.2. The vapor-liquid-solid growth mechanism of self-catalyzed InP nanowires was proved.3. X-ray diffraction and transmission electron microscopy results show that the growth direction of InP nanowire is <111>, and the crystalline structure is zinc-blende with a large number of twin stacking faults which cause"Z"shaped surface defects.4. Compared with the InP substrare, the energy and full width at half maximum of PL spectra measured from the InP nanowires show blue shifts and increase, respectively. The blue shifts and the increase are increased with decreasing nanowires growth temperature. Laser heating has significant impact on the Raman spectrum of the InP nanowires. The Raman TO and LO peaks of the InP nanowires downshift from the InP substrare. The downshifts are decreased with decreasing laser power.