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Title: Stable vicinal step orientations in m- plane GaN

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Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Energy Efficient Materials (CEEM)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Crystal Growth; Journal Volume: 411; Related Information: CEEM partners with the University of California, Santa Barbara (lead); Purdue University; Los Alamos National Laboratory; National Renewable Energy Laboratory
Country of Publication:
United States

Citation Formats

Kelchner, K. M., Kuritzky, L. Y., Nakamura, S., DenBaars, S. P., and Speck, J. S.. Stable vicinal step orientations in m- plane GaN. United States: N. p., 2015. Web. doi:10.1016/j.jcrysgro.2014.10.032.
Kelchner, K. M., Kuritzky, L. Y., Nakamura, S., DenBaars, S. P., & Speck, J. S.. Stable vicinal step orientations in m- plane GaN. United States. doi:10.1016/j.jcrysgro.2014.10.032.
Kelchner, K. M., Kuritzky, L. Y., Nakamura, S., DenBaars, S. P., and Speck, J. S.. 2015. "Stable vicinal step orientations in m- plane GaN". United States. doi:10.1016/j.jcrysgro.2014.10.032.
title = {Stable vicinal step orientations in m- plane GaN},
author = {Kelchner, K. M. and Kuritzky, L. Y. and Nakamura, S. and DenBaars, S. P. and Speck, J. S.},
abstractNote = {},
doi = {10.1016/j.jcrysgro.2014.10.032},
journal = {Journal of Crystal Growth},
number = ,
volume = 411,
place = {United States},
year = 2015,
month = 2
  • We present elucidation of homoepitaxial growth mechanisms on vicinal non-polar surfaces of GaN that is highly important for gaining an understanding of and control thin film surface morphology and properties. Using first-principles calculations, we study the step-flow growth in m-plane GaN based on atomic row nucleation and kink propagation kinetics. Ga–N dimer adsorption onto the m-plane is energetically more favorable than that of Ga and N isolated adatoms. Therefore, we have treated the dimers as the dominant growth species attached to the step edges. By calculating the free energies of sequentially attached Ga–N dimers, we have elucidated that the a-stepmore » edge kink growth proceeds by parallel attachment rather than by across the step edge approach. We found a series of favorable configurations of kink propagation and calculated the free energy and nucleation barriers for kink evolution on five types of step edges (a, +c, -c, +a + c, and -a - c). By changing the chemical potential μGa and the excess chemical potential Δμ, the growth velocities at the five types of edges are controlled by the corresponding kink pair nucleation barrier E* in their free energy profiles. To explore the kink-flow growth instability observed at different Ga/N flux ratios, calculations of kink pairs on the incompact -c and +c-step edges are further performed to study their formation energies. Variations of these step edge morphologies with a tuned chemical environment are consistent with previous experimental observations, including stable diagonal ±a ± c-direction steps. In conclusion, our work provides a first-principles approach to explore step growth and surface morphology of the vicinal m-plane GaN, which is applicable to analyze and control the step-flow growth of other binary thin films.« less
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  • The growth mechanisms of (Al,Ga)As lateral superlattices (LSL) on GaAs(100) and GaAs (110) vicinal surfaces were studied using transmission electron microscopy (TEM) and Monte Carlo simulations. In GaAs(100) surfaces, spontaneous formation of a LSL from (AlAs){sub 1} (GaAs){sub 1} short period superlattices; is explained by a vertical exchange reaction model. This mechanism may be the underlying cause of poor lateral segregation in conventional fractional layer (Al,Ga)As LSL. Growth on vicinal GaAs(110) surfaces leads to periodic faceting. Cross-sectional TEM images were compared with simulation of a step-flow model to understand the process of step bunching and the evolution of periodic microfacets.more » 21 refs., 3 figs.« less
  • The diffraction intensities of He atoms scattered from vicinal Cu(211) and Cu(511) surfaces have been measured with a high angular resolution over a wide range of incident energies from 8 to 82 meV. Close-coupling scattering calculations with a corrugated Morse potential were performed to obtain the corrugation parameters for the first three complex Fourier coefficients. The energy-dependent corrugation profiles determined from the best fit indicate that the corrugation predicted by a simple hard-sphere model is considerably smeared out at the small electron densities far from the surface probed by the He atoms. A comparison with Eikonal calculations demonstrates that hardmore » corrugated wall Eikonal models are not adequate for the structural analysis of stepped surfaces. {copyright} {ital 1996 The American Physical Society.}« less