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Title:Bottom-up growth of III-V compound semiconductor nanowires by selective lateral/area epitaxy
Author(s):Choi, Wonsik
Director of Research:Li, Xiuling
Doctoral Committee Chair(s):Li, Xiuling
Doctoral Committee Member(s):Lyding, Joseph W; Lee, Minjoo L; Nam, Sungwoo
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):semiconductor nanowire
selective lateral epitaxy
selective area epitaxy
Abstract:Bottom-up grown III-V compound semiconductor nanowires (NWs) provide a novel building block for electrical and optical devices. Bottom-up III-V NWs can be synthesized by either a vapor-liquid-solid (VLS) or selective area epitaxy (SAE) mechanism. Under the specific VLS NW growth conditions, planar self-aligned NWs can be grown on top of a substrate under a selective lateral epitaxy (SLE) mechanism. In this thesis research, first, the realization of lateral multiple p-n junction gallium arsenide (GaAs) SLE NW grown by metal-organic chemical vapor deposition (MOCVD) reactor is presented. Scanning microwave impedance microscopy (sMIM) and infrared scattering-type near-field optical microscopy (IR-SNOM) scans on top of the NW suggested that p-type zinc dopants are accumulated at twin-plane boundaries of NW. The electrical properties of the SLE GaAs lateral p-n junction were analyzed by measuring two-terminal I-V characteristics of arrays of p-n NW diodes. The I-V characteristics of the devices indicated that the lateral p-n junction was successfully realized with a high rectification ratio of ~106. The gallium phosphide (GaP) SAE NW growth on top of a silicon (Si) substrate will be also introduced. Systemic studies were performed by modulating the following three NW growth conditions: TMGa flow rate, growth temperature, and V/III ratio. By controlling the NW growth parameters, a 97.5% yield of hexagonal NWs was grown on an area of 400 µm × 400 µm. The morphology of the NWs was inspected with a scanning electron microscope (SEM). X-ray diffraction (XRD) analysis was performed on the GaP NWs, and 6.3016 Å of wurtzite (WZ) GaP c-lattice parameter was extracted. Vertical arrays of GaP p-n and p-i-n NW diodes were fabricated. The ideality factor and rectification ratio of p-n GaP NW diode were measured 7 and 10, respectively. The ideality factor and the rectification ratio could be improved to 3.7 and 1000 by introducing an undoped intrinsic layer between n-type and p-type GaP NW.
Issue Date:2019-12-05
Rights Information:Chapter 2 was reproduced with the permission from [W. Choi et al., "Direct electrical probing of periodic modulation of zinc-dopant distributions in planar gallium arsenide nanowires," ACS Nano, vol. 11, no. 2, pp. 1530-1539, 2017.] Copyright [2017] American Chemical Society.
Date Available in IDEALS:2020-03-02
Date Deposited:2019-12

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