Brittle fracture toughnesses of GaN and AlN from first-principles surface-energy calculations

C. E. Dreyer; A. Janotti; C. G. Van De Walle

doi:10.1063/1.4921855

Brittle fracture toughnesses of GaN and AlN from first-principles surface-energy calculations

C. E. Dreyer
, A. Janotti
, C. G. Van De Walle

Physics and Astronomy

Stony Brook University

University of California at Santa Barbara

Research output: Contribution to journal › Article › peer-review

25 Scopus citations

Abstract

Cracks are a major limitation for the growth of III-nitride bulk crystals and thick epitaxial films. The propensity for a crack to propagate on a given plane is determined by the anisotropic fracture toughness, Γ. Using first-principles surface-energy calculations, we have determined toughnesses for brittle fracture (Γ_b) in GaN and AlN, for cracks on the nonpolar { 10 1 ¯ 0 } m-and { 11 2 ¯ 0 } a planes, and the polar (0001) + (000 1 ¯) c plane. For both materials, Γ_b values for cracks on the nonpolar planes are similar, and significantly smaller than for the c plane. Calculated critical thicknesses for AlGaN grown on GaN correctly predict the fracture planes in polar and nonpolar growth.

Original language	English
Article number	212103
Journal	Applied Physics Letters
Volume	106
Issue number	21
DOIs	https://doi.org/10.1063/1.4921855
State	Published - May 25 2015

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title = "Brittle fracture toughnesses of GaN and AlN from first-principles surface-energy calculations",

abstract = "Cracks are a major limitation for the growth of III-nitride bulk crystals and thick epitaxial films. The propensity for a crack to propagate on a given plane is determined by the anisotropic fracture toughness, Γ. Using first-principles surface-energy calculations, we have determined toughnesses for brittle fracture (Γb) in GaN and AlN, for cracks on the nonpolar \{ 10 1 ¯ 0 \} m-and \{ 11 2 ¯ 0 \} a planes, and the polar (0001) + (000 1 ¯) c plane. For both materials, Γb values for cracks on the nonpolar planes are similar, and significantly smaller than for the c plane. Calculated critical thicknesses for AlGaN grown on GaN correctly predict the fracture planes in polar and nonpolar growth.",

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T1 - Brittle fracture toughnesses of GaN and AlN from first-principles surface-energy calculations

AU - Dreyer, C. E.

AU - Janotti, A.

AU - Van De Walle, C. G.

PY - 2015/5/25

Y1 - 2015/5/25

N2 - Cracks are a major limitation for the growth of III-nitride bulk crystals and thick epitaxial films. The propensity for a crack to propagate on a given plane is determined by the anisotropic fracture toughness, Γ. Using first-principles surface-energy calculations, we have determined toughnesses for brittle fracture (Γb) in GaN and AlN, for cracks on the nonpolar { 10 1 ¯ 0 } m-and { 11 2 ¯ 0 } a planes, and the polar (0001) + (000 1 ¯) c plane. For both materials, Γb values for cracks on the nonpolar planes are similar, and significantly smaller than for the c plane. Calculated critical thicknesses for AlGaN grown on GaN correctly predict the fracture planes in polar and nonpolar growth.

AB - Cracks are a major limitation for the growth of III-nitride bulk crystals and thick epitaxial films. The propensity for a crack to propagate on a given plane is determined by the anisotropic fracture toughness, Γ. Using first-principles surface-energy calculations, we have determined toughnesses for brittle fracture (Γb) in GaN and AlN, for cracks on the nonpolar { 10 1 ¯ 0 } m-and { 11 2 ¯ 0 } a planes, and the polar (0001) + (000 1 ¯) c plane. For both materials, Γb values for cracks on the nonpolar planes are similar, and significantly smaller than for the c plane. Calculated critical thicknesses for AlGaN grown on GaN correctly predict the fracture planes in polar and nonpolar growth.

UR - https://www.scopus.com/pages/publications/84930626892

U2 - 10.1063/1.4921855

DO - 10.1063/1.4921855

M3 - Article

SN - 0003-6951

VL - 106

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 21

M1 - 212103

ER -

Brittle fracture toughnesses of GaN and AlN from first-principles surface-energy calculations

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