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Title: Influence of substrate material, orientation, and surface termination on GaN nanowire growth

Abstract

In this work, we investigate the fundamental role of the substrate material, surface orientation, and termination on GaN nanowire (NW) nucleation and growth. First of all, the use of a patterned a-Si/diamond substrate confirms that NW shape and dimension are mainly determined by the applied growth conditions instead of the nature of the substrate. More important is the surface orientation as it defines growth direction and epitaxial relationship towards the GaN NWs, where both (111) and (100) surfaces yield NW growth for equivalent growth conditions. (110) substrates are found to be not suited for NW growth. Finally, the surface termination of diamond is demonstrated to survive the employed growth conditions and, therefore, to affect the nucleation of nanowires and the electronic properties of the heterointerface by its surface dipoles. This difference in nucleation is exploited as an alternative approach for selective area growth without deposition of a foreign mask material, which might also be transferable to other substrates.

Authors:
; ; ; ; ;  [1]
  1. Walter Schottky Institut and Physics Department, Technische Universität München, Am Coulombwall 4, 85748 Garching (Germany)
Publication Date:
OSTI Identifier:
22314562
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DEPOSITION; DIAMONDS; DIPOLES; EPITAXY; GALLIUM NITRIDES; NUCLEATION; ORIENTATION; QUANTUM WIRES; SHAPE; SUBSTRATES; SURFACES

Citation Formats

Schuster, Fabian, E-mail: Fabian.Schuster@wsi.tum.de, Weiszer, Saskia, Hetzl, Martin, Winnerl, Andrea, Garrido, Jose A., and Stutzmann, Martin. Influence of substrate material, orientation, and surface termination on GaN nanowire growth. United States: N. p., 2014. Web. doi:10.1063/1.4892113.
Schuster, Fabian, E-mail: Fabian.Schuster@wsi.tum.de, Weiszer, Saskia, Hetzl, Martin, Winnerl, Andrea, Garrido, Jose A., & Stutzmann, Martin. Influence of substrate material, orientation, and surface termination on GaN nanowire growth. United States. doi:10.1063/1.4892113.
Schuster, Fabian, E-mail: Fabian.Schuster@wsi.tum.de, Weiszer, Saskia, Hetzl, Martin, Winnerl, Andrea, Garrido, Jose A., and Stutzmann, Martin. Thu . "Influence of substrate material, orientation, and surface termination on GaN nanowire growth". United States. doi:10.1063/1.4892113.
@article{osti_22314562,
title = {Influence of substrate material, orientation, and surface termination on GaN nanowire growth},
author = {Schuster, Fabian, E-mail: Fabian.Schuster@wsi.tum.de and Weiszer, Saskia and Hetzl, Martin and Winnerl, Andrea and Garrido, Jose A. and Stutzmann, Martin},
abstractNote = {In this work, we investigate the fundamental role of the substrate material, surface orientation, and termination on GaN nanowire (NW) nucleation and growth. First of all, the use of a patterned a-Si/diamond substrate confirms that NW shape and dimension are mainly determined by the applied growth conditions instead of the nature of the substrate. More important is the surface orientation as it defines growth direction and epitaxial relationship towards the GaN NWs, where both (111) and (100) surfaces yield NW growth for equivalent growth conditions. (110) substrates are found to be not suited for NW growth. Finally, the surface termination of diamond is demonstrated to survive the employed growth conditions and, therefore, to affect the nucleation of nanowires and the electronic properties of the heterointerface by its surface dipoles. This difference in nucleation is exploited as an alternative approach for selective area growth without deposition of a foreign mask material, which might also be transferable to other substrates.},
doi = {10.1063/1.4892113},
journal = {Journal of Applied Physics},
number = 5,
volume = 116,
place = {United States},
year = {Thu Aug 07 00:00:00 EDT 2014},
month = {Thu Aug 07 00:00:00 EDT 2014}
}
  • Series of GaN nanowires (NW) with controlled diameters (160–500 nm) and heights (420–1100 nm) were homoepitaxially grown on three different templates: GaN/Si(111), GaN/AlN/Si(111), and GaN/sapphire(0001). Transmission electron microscopy reveals a strong influence of the NW diameter on dislocation filtering effect, whereas photoluminescence measurements further relate this effect to the GaN NWs near-bandgap emission efficiency. Although the templates' quality has some effects on the GaN NWs optical and structural properties, the NW diameter reduction drives the dislocation filtering effect to the point where a poor GaN template quality becomes negligible. Thus, by a proper optimization of the homoepitaxial GaN NWs growth, the propagationmore » of dislocations into the NWs can be greatly prevented, leading to an exceptional crystal quality and a total dominance of the near-bandgap emission over sub-bandgap, defect-related lines, such as basal stacking faults and so called unknown exciton (UX) emission. In addition, a correlation between the presence of polarity inversion domain boundaries and the UX emission lines around 3.45 eV is established.« less
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  • The surface structures of ionic zinc-blende CdTe (001), (110), (111), and (211) surfaces are systematically studied by first-principles density functional calculations. Based on the surface structures and surface energies, we identify the detrimental twinning appearing in molecular beam epitaxy (MBE) growth of II-VI compounds as the (111) lamellar twin boundaries. To avoid the appearance of twinning in MBE growth, we propose the following selection rules for choosing optimal substrate orientations: (1) the surface should be nonpolar so that there is no large surface reconstructions that could act as a nucleation center and promote the formation of twins; (2) the surfacemore » structure should have low symmetry so that there are no multiple equivalent directions for growth. These straightforward rules, in consistent with experimental observations, provide guidelines for selecting proper substrates for high-quality MBE growth of II-VI compounds.« less