This dissertation work is a study of the growth kinematics, synthesis strategies and intrinsic properties of InSb nanowires (NWs). The highlights of this work include a study of the effect of the growth parameters on the composition and crystallinity of NWs. A change in the temperature ramp-up rate as the substrate was heated to reach the NW growth temperature resulted in NWs that were either crystalline or amorphous. The as-grown NWs were found to have very different optical and electrical properties. The growth mechanism for crystalline NWs is the standard vapor-liquid-solid growth mechanism. This work proposes two possible growth mechanisms for amorphous NWs. The amorphous InSb NWs were found to be very sensitive to laser radiation and to heat treatment. Raman spectroscopy measurements on these NWs showed that intense laser light induced localized crystallization, most likely due to radiation induced annealing of defects in the region hit by the laser beam. Electron transport measurements revealed non-linear current-voltage characteristics that could not be explained by a Schottky diode behavior. Analysis of the experimental data showed that electrical conduction in this material is governed by space charge limited current (SCLC) in the high bias-field region and by Ohm's law in the low bias region. Temperature dependent conductivity measurements on these NWs revealed that conduction follows Mott variable range hopping mechanism at low temperatures and near neighbor hopping mechanism at high temperature. Low-temperature annealing of the amorphous NWs in an inert environment was found to induce a phase transformation of the NWs, causing their crystallinity to be enhanced. This thesis also proposes a new and low-cost strategy to grow p-type InSb NWs on InSb films grown on glass substrate. The high quality polycrystalline InSb film was used as the host on which the NWs were grown. The NWs with an average diameter of 150 nm and length of 20 μm were shown to have hole concentration of about 1017 cm-3 and mobility of about 1000 cm2V-1s-1. This thesis also proposes a strategy for the fabrication of metal-semiconductor nanocomposites. InSb NWs grown by electrochemical deposition were decorated with nanometer sized Au and Ag nanoparticles to form the nanocomposite.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc1404545 |
| Date | 12 1900 |
| Creators | Algarni, Zaina Sluman |
| Contributors | Neogi, Arup, Rout, Bibhudutta, Littler, Chris, Philipose, Usha |
| Publisher | University of North Texas |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | xviii, 135 pages, Text |
| Rights | Public, Algarni, Zaina Sluman, Copyright, Copyright is held by the author, unless otherwise noted. All rights Reserved. |
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