Polarization anisotropy in GaN films for different nonpolar orientations studied by polarized photoreflectance spectroscopy

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Misra P., Behn U., Brandt O., Grahn H., Imer B. , Nakamura S., ...More

APPLIED PHYSICS LETTERS, vol.88, no.16, 2006 (Journal Indexed in SCI)

• Publication Type: Article / Article
• Volume: 88 Issue: 16
• Publication Date: 2006
• Doi Number: 10.1063/1.2198086
• Title of Journal : APPLIED PHYSICS LETTERS

Abstract

We use photoreflectance (PR) spectroscopy to study the electronic band structure modification of GaN films grown along different nonpolar orientations due to biaxial, anisotropic in-plane strain. The exciton transition energies of an unstrained, high-quality C-plane GaN film are used to accurately determine the crystal-field and spin-orbit splitting energies. For films with a nonpolar orientation, the resonant features observed in the PR spectra exhibit a strong in-plane polarization anisotropy and different transition energies from the ones measured in the C-plane GaN film. The deformation potential D-5 is accurately determined from four GaN films with a nonpolar orientation using the measured energies together with the polarization properties and out-of-plane strain. (c) 2006 American Institute of Physics.