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Nanowire Growth and Characterization in the AlGaInP Material System

Berg, Alexander LU (2016)
Abstract
Nanowires are future building blocks for optoelectronic devices. Due to their small dimensions consumption of rare semiconductor material is reduced during device fabrication, which is beneficial with respect to rare sources as compared to conventional layer structures where thicknesses of several hundreds of micrometers are typical. Nanowires can be used to design light-emitting diodes.

This thesis focuses on the AlGaInP material system being able to tune the visible emission from green to red. Gallium phosphide has been predicted to have a direct band gap in wurtzite crystal phase, which is necessary for light emitters. Nanowires grown at low temperatures often incorporate carbon in competitive radial growth. Therefore, in situ... (More)
Nanowires are future building blocks for optoelectronic devices. Due to their small dimensions consumption of rare semiconductor material is reduced during device fabrication, which is beneficial with respect to rare sources as compared to conventional layer structures where thicknesses of several hundreds of micrometers are typical. Nanowires can be used to design light-emitting diodes.

This thesis focuses on the AlGaInP material system being able to tune the visible emission from green to red. Gallium phosphide has been predicted to have a direct band gap in wurtzite crystal phase, which is necessary for light emitters. Nanowires grown at low temperatures often incorporate carbon in competitive radial growth. Therefore, in situ etching by different halides such as hydrogen chloride and hydrogen bromide during growth as well as its effect on the morphology, crystal structure and optical properties were investigated.

We have developed ternary GaInP nanowire growth with homogeneous composition along the growth axis that can be used as a “substrate template” for radial growth with lattice constants that do not exist in conventional binary semiconductor substrates. This gives more freedom in designing structures optimized for specific wavelengths. Furthermore, one study has been made on growth without seed particle, the so-called selective-area growth being crucial for mass-production nanowire epitaxy.

In order to optimize growth with respect to identical nanowires, they should be grown from a pattern where the distance between two nanowires is identical because of more controlled growth. We have developed the technique of nanoimprint lithography further, optimized for light emission. Therewith, lattice-matched core-shell nanowire structures were grown and investigated by advanced characterization techniques. Finally, we demonstrated our core-shell nanowires to be useful for light-emitting applications as we observed red light upon electrical injection. (Less)
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author
supervisor
opponent
  • Dr.-Ing. Werner Prost, University of Duisburg-Essen, Germany
organization
publishing date
type
Thesis
publication status
published
keywords
Nanowire, MOVPE, in situ etching, ternary semiconductor, AlGaInP, light-emitting diodes
defense location
Rydbergsalen, Department of Physics, Sölvegatan 14, Lund University, Faculty of Engineering
defense date
2016-10-14 09:30
ISBN
978-91-7623-796-0
language
English
LU publication?
yes
id
313aae63-a2d2-4c93-8145-b8f41ba59156
date added to LUP
2016-08-31 10:13:17
date last changed
2016-09-19 08:45:20
@misc{313aae63-a2d2-4c93-8145-b8f41ba59156,
  abstract     = {Nanowires are future building blocks for optoelectronic devices. Due to their small dimensions consumption of rare semiconductor material is reduced during device fabrication, which is beneficial with respect to rare sources as compared to conventional layer structures where thicknesses of several hundreds of micrometers are typical. Nanowires can be used to design light-emitting diodes.<br/><br/>This thesis focuses on the AlGaInP material system being able to tune the visible emission from green to red. Gallium phosphide has been predicted to have a direct band gap in wurtzite crystal phase, which is necessary for light emitters. Nanowires grown at low temperatures often incorporate carbon in competitive radial growth. Therefore, in situ etching by different halides such as hydrogen chloride and hydrogen bromide during growth as well as its effect on the morphology, crystal structure and optical properties were investigated.<br/><br/>We have developed ternary GaInP nanowire growth with homogeneous composition along the growth axis that can be used as a “substrate template” for radial growth with lattice constants that do not exist in conventional binary semiconductor substrates. This gives more freedom in designing structures optimized for specific wavelengths. Furthermore, one study has been made on growth without seed particle, the so-called selective-area growth being crucial for mass-production nanowire epitaxy.<br/><br/>In order to optimize growth with respect to identical nanowires, they should be grown from a pattern where the distance between two nanowires is identical because of more controlled growth. We have developed the technique of nanoimprint lithography further, optimized for light emission. Therewith, lattice-matched core-shell nanowire structures were grown and investigated by advanced characterization techniques. Finally, we demonstrated our core-shell nanowires to be useful for light-emitting applications as we observed red light upon electrical injection.},
  author       = {Berg, Alexander},
  isbn         = {978-91-7623-796-0},
  keyword      = {Nanowire,MOVPE,in situ etching,ternary semiconductor,AlGaInP,light-emitting diodes},
  language     = {eng},
  month        = {09},
  title        = {Nanowire Growth and Characterization in the AlGaInP Material System},
  year         = {2016},
}