skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge

Abstract

By means of a hybrid density-functional method, we investigate the tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. We consider [001], [111], and [110] uniaxial tensility and (001), (111), and (110) biaxial tensility. Under the condition of no normal stress, we determine both normal compression and internal strain, namely, relative displacement of two atoms in the primitive unit cell, by minimizing the total energy. We identify those strain types which can induce the band-gap transition, and evaluate the critical strain coefficient where the gap transition occurs. Either normal compression or internal strain operates unfavorably to induce the gap transition, which raises the critical strain coefficient or even blocks the transition. We also examine how each type of tensile strain decreases the band-gap energy, depending on its orientation. Our analysis clearly shows that synergistic operation of strain orientation and band anisotropy has a great influence on the gap transition and the gap energy.

Authors:
; ; ;  [1]
  1. Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213 (Japan)
Publication Date:
OSTI Identifier:
22489482
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 118; Journal Issue: 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; ATOMS; COMPRESSION; DENSITY FUNCTIONAL METHOD; HYBRIDIZATION; ORIENTATION; STRAINS; STRESSES

Citation Formats

Inaoka, Takeshi, Furukawa, Takuro, Toma, Ryo, and Yanagisawa, Susumu. Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. United States: N. p., 2015. Web. doi:10.1063/1.4930225.
Inaoka, Takeshi, Furukawa, Takuro, Toma, Ryo, & Yanagisawa, Susumu. Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. United States. doi:10.1063/1.4930225.
Inaoka, Takeshi, Furukawa, Takuro, Toma, Ryo, and Yanagisawa, Susumu. Mon . "Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge". United States. doi:10.1063/1.4930225.
@article{osti_22489482,
title = {Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge},
author = {Inaoka, Takeshi and Furukawa, Takuro and Toma, Ryo and Yanagisawa, Susumu},
abstractNote = {By means of a hybrid density-functional method, we investigate the tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. We consider [001], [111], and [110] uniaxial tensility and (001), (111), and (110) biaxial tensility. Under the condition of no normal stress, we determine both normal compression and internal strain, namely, relative displacement of two atoms in the primitive unit cell, by minimizing the total energy. We identify those strain types which can induce the band-gap transition, and evaluate the critical strain coefficient where the gap transition occurs. Either normal compression or internal strain operates unfavorably to induce the gap transition, which raises the critical strain coefficient or even blocks the transition. We also examine how each type of tensile strain decreases the band-gap energy, depending on its orientation. Our analysis clearly shows that synergistic operation of strain orientation and band anisotropy has a great influence on the gap transition and the gap energy.},
doi = {10.1063/1.4930225},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 10,
volume = 118,
place = {United States},
year = {2015},
month = {9}
}