2024-03-28T22:23:10Zhttps://keep.lib.asu.edu/oai/requestoai:keep.lib.asu.edu:node-1564402021-08-27T02:47:01Zoai_pmh:all156440
https://hdl.handle.net/2286/R.I.49297
http://rightsstatements.org/vocab/InC/1.0/
All Rights Reserved
2018
2020-05-07T08:36:28
xx, 211 pages : color illlustrations
Doctoral Dissertation
Academic theses
Text
eng
Hashemi Amiri, Seyed Ebrahim
Ning, Cun-Zheng
Petuskey, William
Yu, Hongbin
Arizona State University
Partial requirement for: Ph.D., Arizona State University, 2018
Includes bibliographical references (pages 192-211)
Field of study: Chemistry
The larger tolerance to lattice mismatch in growth of semiconductor nanowires (NWs) offers much more flexibility for achieving a wide range of compositions and bandgaps via alloying within a single substrate. The bandgap of III-V InGaAsP alloy NWs can be tuned to cover a wide range of (0.4, 2.25) eV, appealing for various optoelectronic applications such as photodetectors, solar cells, Light Emitting Diodes (LEDs), lasers, etc., given the existing rich knowledge in device fabrication based on these materials.<br/><br/>This dissertation explores the growth of InGaAsP alloys using a low-cost method that could be potentially important especially for III-V NW-based solar cells. The NWs were grown by Vapor-Liquid-Solid (VLS) and Vapor-Solid (VS) mechanisms using a Low-Pressure Chemical Vapor Deposition (LPCVD) technique. The concept of supersaturation was employed to control the morphology of NWs through the interplay between VLS and VS growth mechanisms. Comprehensive optical and material characterizations were carried out to evaluate the quality of the grown materials.<br/><br/>The growth of exceptionally high quality III-V phosphide NWs of InP and GaP was studied with an emphasis on the effects of vastly different sublimation rates of the associated III and V elements. The incorporation of defects exerted by deviation from stoichiometry was examined for GaP NWs, with an aim towards maximization of bandedge-to-defect emission ratio. In addition, a VLS-VS assisted growth of highly stoichiometric InP thin films and nano-networks with a wide temperature window from 560◦C to 720◦C was demonstrated. Such growth is shown to be insensitive to the type of substrates such as silicon, InP, and fused quartz. The dual gradient method was exploited to grow composition-graded ternary alloy NWs of InGaP, InGaAs, and GaAsP with different bandgaps ranging from 0.6 eV to 2.2 eV, to be used for making laterally-arrayed multiple bandgap (LAMB) solar cells. Furthermore, a template-based growth of the NWs was attempted based on the Si/SiO2 substrate. Such platform can be used to grow a wide range of alloy nanopillar materials, without being limited by typical lattice mismatch, providing a low cost universal platform for future PV solar cells.
Chemistry
Materials Science
engineering
Alloys
Bandgap
InGaAsP
Optoelectronics
Semiconductor Nanowires
Gallium alloys
Solar Cells
Semiconductors
Nanowires
Growth and characterization of InGaAsP alloy nanowires with widely tunable bandgaps for optoelectronic applications