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Title: Molecular beam epitaxy of InN dots on nitrided sapphire

Abstract

A series of self-assembled InN dots are grown by radio frequency (RF) plasma-assisted molecular beam epitaxy (MBE) directly on nitrided sapphire. Initial nitridation of the sapphire substrates at 900 C results in the formation of a rough AlN surface layer, which acts as a very thin buffer layer and facilitates the nucleation of the InN dots according to the Stranski-Krastanow growth mode, with a wetting layer of {approx}0.9 nm. Atomic force microscopy (AFM) reveals that well-confined InN nanoislands with the greatest height/width at half-height ratio of 0.64 can be grown at 460 C. Lower substrate temperatures result in a reduced aspect ratio due to a lower diffusion rate of the In adatoms, whereas the thermal decomposition of InN truncates the growth at T>500 C. The densities of separated dots vary between 1.0 x 10{sup 10} cm{sup -2} and 2.5 x 10{sup 10} cm{sup -2} depending on the growth time. Optical response of the InN dots under laser excitation is studied with apertureless near-field scanning optical microscopy and photoluminescence spectroscopy, although no photoluminescence is observed from these samples. In view of the desirable implementation of InN nanostructures into photonic devices, the results indicate that nitrided sapphire is a suitable substrate formore » growing self-assembled InN nanodots.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. Basic Energy Sciences; Swiss National Science Foundation (SNSF)
OSTI Identifier:
922861
Report Number(s):
LBNL-62583
Journal ID: ISSN 0022-0248; JCRGAE; R&D Project: 400101; BnR: KC0203010; TRN: US200804%%1238
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Crystal Growth; Journal Volume: 304; Journal Issue: 2; Related Information: Journal Publication Date: 06/15/2007
Country of Publication:
United States
Language:
English
Subject:
36; ASPECT RATIO; ATOMIC FORCE MICROSCOPY; BUFFERS; DIFFUSION; EXCITATION; IMPLEMENTATION; LASERS; MOLECULAR BEAM EPITAXY; NANOSTRUCTURES; NITRIDATION; NUCLEATION; OPTICAL MICROSCOPY; PHOTOLUMINESCENCE; PYROLYSIS; SAPPHIRE; SPECTROSCOPY; SUBSTRATES

Citation Formats

Romanyuk, Yaroslav E., Dengel, Radu-Gabriel, Stebounova, LarissaV., and Leone, Stephen R. Molecular beam epitaxy of InN dots on nitrided sapphire. United States: N. p., 2007. Web. doi:10.1016/j.jcrysgro.2007.01.048.
Romanyuk, Yaroslav E., Dengel, Radu-Gabriel, Stebounova, LarissaV., & Leone, Stephen R. Molecular beam epitaxy of InN dots on nitrided sapphire. United States. doi:10.1016/j.jcrysgro.2007.01.048.
Romanyuk, Yaroslav E., Dengel, Radu-Gabriel, Stebounova, LarissaV., and Leone, Stephen R. Fri . "Molecular beam epitaxy of InN dots on nitrided sapphire". United States. doi:10.1016/j.jcrysgro.2007.01.048. https://www.osti.gov/servlets/purl/922861.
@article{osti_922861,
title = {Molecular beam epitaxy of InN dots on nitrided sapphire},
author = {Romanyuk, Yaroslav E. and Dengel, Radu-Gabriel and Stebounova, LarissaV. and Leone, Stephen R.},
abstractNote = {A series of self-assembled InN dots are grown by radio frequency (RF) plasma-assisted molecular beam epitaxy (MBE) directly on nitrided sapphire. Initial nitridation of the sapphire substrates at 900 C results in the formation of a rough AlN surface layer, which acts as a very thin buffer layer and facilitates the nucleation of the InN dots according to the Stranski-Krastanow growth mode, with a wetting layer of {approx}0.9 nm. Atomic force microscopy (AFM) reveals that well-confined InN nanoislands with the greatest height/width at half-height ratio of 0.64 can be grown at 460 C. Lower substrate temperatures result in a reduced aspect ratio due to a lower diffusion rate of the In adatoms, whereas the thermal decomposition of InN truncates the growth at T>500 C. The densities of separated dots vary between 1.0 x 10{sup 10} cm{sup -2} and 2.5 x 10{sup 10} cm{sup -2} depending on the growth time. Optical response of the InN dots under laser excitation is studied with apertureless near-field scanning optical microscopy and photoluminescence spectroscopy, although no photoluminescence is observed from these samples. In view of the desirable implementation of InN nanostructures into photonic devices, the results indicate that nitrided sapphire is a suitable substrate for growing self-assembled InN nanodots.},
doi = {10.1016/j.jcrysgro.2007.01.048},
journal = {Journal of Crystal Growth},
number = 2,
volume = 304,
place = {United States},
year = {Fri Apr 20 00:00:00 EDT 2007},
month = {Fri Apr 20 00:00:00 EDT 2007}
}
  • The polarity of molecular-beam epitaxy grown ZnO films was controlled on nitrided c-sapphire substrate by modifying the interface between the ZnO buffer layer and the nitrided sapphire. The ZnO film grown on nitrided sapphire was proven to be Zn-polar while the O-polar one was obtained by using gallium predeposition on nitrided sapphire, which was confirmed by coaxial impact collision ion scattering spectroscopy and chemical etching effect. The Zn-polar ZnO film showed higher growth rate, slightly better quality, and different surface morphology in comparison to the O-polar one.
  • No abstract prepared.
  • We investigated the growth behaviors of InN quantum dots (QDs) on N-polarity GaN by molecular-beam epitaxy. The N-polarity growth has been intentionally used to raise the temperature to facilitate formation of high-quality dots. It was found that the InN QDs could be grown up to 550 deg. C the Stranski-Kastanov growth mode with the wetting layer thickness of about 1 monolayer, which was confirmed by the simultaneous in situ observations of reflection high-energy electron diffraction and spectroscopic ellipsometry. The density and the diameter of typical InN QDs grown at 450-550 deg. C were the order of 10{sup 11} cm{sup -2}more » and 15-20 nm, respectively.« less
  • Electron microscopy has been used to characterize the microstructure of InN quantum dots (QDs) grown by molecular-beam epitaxy on GaN(0001)/AlN(0001)/sapphire substrates at 425 deg. C under slightly group III-rich conditions. Observations in plan-view and cross-section geometries established that the large majority of the InN QDs were invariably associated with threading dislocations in the underlying GaN buffer layer having edge components. Periodic, primarily hexagonal, arrays of misfit dislocations separated by {approx}2.8 nm were observed at the InN QD/GaN interface, indicating that the QDs were almost completely relaxed. No evidence for an InN wetting layer was obtained either in situ by reflectionmore » high-energy electron diffraction or ex situ by transmission electron microscopy.« less
  • InN quantum dots (QDs) were grown on Si (111) by epitaxial Stranski-Krastanow growth mode using plasma-assisted molecular beam epitaxy. Single-crystalline wurtzite structure of InN QDs was verified by the x-ray diffraction and transmission electron microscopy. Scanning tunneling microscopy has been used to probe the structural aspects of QDs. A surface bandgap of InN QDs was estimated from scanning tunneling spectroscopy (STS) I-V curves and found that it is strongly dependent on the size of QDs. The observed size-dependent STS bandgap energy shifts with diameter and height were theoretical explained based on an effective mass approximation with finite-depth square-well potential model.