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Stress relaxation of AlGaN on nonpolar m-plane GaN substrate

Accepted version
Peer-reviewed

Type

Article

Change log

Abstract

jats:pThe stress relaxation with increasing thickness of metal-organic vapor phase epitaxy grown Al0.19Ga0.81N on quasi-bulk (101¯0) m-plane GaN substrates was investigated by x-ray diffraction. The anisotropic in-plane stress leads to an orthorhombic distortion of the lattice, which requires special mathematical treatment. Extending earlier works, we developed a method to calculate the distortion along [12¯10], [0001], and [101¯0] and obtained the lattice parameters, Al content, and strain values. The stress relaxation along the two in-plane directions involves two different mechanisms. First, the stress along [12¯10] relaxes by the onset of misfit dislocations through the {101¯0}⟨12¯10⟩ slip system while for thicker layers the stress along [0001] relaxes by crack formation. Comparing the cathodoluminescence emission at room temperature with the expected bandgap showed that both tensile in-plane strains along [12¯10] and [0001] decrease the bandgap.</jats:p>

Description

Keywords

40 Engineering

Journal Title

Journal of Applied Physics

Conference Name

Journal ISSN

0021-8979
1089-7550

Volume Title

133

Publisher

AIP Publishing