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The Preparation And Applied Research Of GaM/InN Core-shell Nanowires

Posted on:2019-07-05Degree:MasterType:Thesis
Country:ChinaCandidate:Q P QiFull Text:PDF
GTID:2321330566467826Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
The core-shell nanowires is a heterogeneous structure composed of two materials.This unique structure combines the characteristics of two core-shell materials,and has novel properties.Adjusting the core-shell ratio to regulate the electronic structure and optical properties of materials can satisfy the flexibility of optoelectronic device design and broaden the application of nanomaterials in the field of optoelectronics.In this paper,GaN/InN core-shell nanowires have been studied in both experimental preparation and theoretical calculations.First,GaN/InN core-shell nanowires heterostructure were prepared in two steps by chemical vapor deposition(CVD).The preparation of heterostructure of GaN/InN core-shell nanowires with different In precursors and growth conditions was experimentally studied.By analyzing the growth mechanism of this heterogeneous structure,the results show the growth of the GaN nucleus follows the VLS mechanism in the first step.The growth of the InN shell follows the VS mechanism in the second step.The photoluminescence(PL)spectra of GaN nanowires show that there is an ultraviolet emission peak at 362 nm(3.42 eV),which is mainly attributed to band edge emission.The photoluminescence(PL)spectra of GaN/InN core-shell nanowires heterostructure show a violet emission peak at 404 nm(3.06 eV).The emission peaks are red-shifted from UV light into visible light compared with GaN nanowires,which is attributed to decrease of the bandgap.Then,the heterostructure of GaN/InN core-shell nanowires was studied based on the first-principle.Theoretical calculations show that the bandgap are related to core-shell ratio of GaN/InN core-shell nanowires and the diameter of nanowires.In the case of the same nanowires diameter,the bandgap increased with the increase of the ratio of GaN.When the ratio of core-shell fixed,the bandgap decreased with the increase of the nanowires diameter.The main peak in the imaginary part of the dielectric function with the GaN/InN core-shell nanowires heterostructure moves in the direction of low energy with the reduction of the proportion of core and shell.The entire absorption spectrum range from the ultraviolet light into the visible light band.The above studies show that the experimental tests is consistent with the theoretical calculations.Therefore,the heterostructure of GaN/InN core-shell nanowires achieves the regulation of the bandgap and optical properties,resulting in an application range from ultraviolet to visible.
Keywords/Search Tags:GaN, InN, Core-Shell Nanowires, Heterostructure, Chemical Vapor Deposition, First-Principle, Optical Properties
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