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Semipolar GaN (semipolar + gan)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Polarization of eigenmodes in laser diode waveguides on semipolar and nonpolar GaN

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 1-2 2010
Jens Rass
Abstract Recent calculations of the eigenmodes in waveguides grown on semipolar GaN suggest that the optical polarization of the emitted light as well as the optical gain depends on the orientation of the resonator. Our measurements on separate confinement heterostructures on semipolar (112) and (102) GaN show that for laser resonators along the semipolar [11] and [011] directions (i.e. the projection of the c -axis onto the plane of growth) the threshold for amplified spontaneous emission is lower than for the nonpolar direction and that the stimulated emission is linearly polarized as TE mode. For the waveguide structures along the nonpolar [100] or [110] direction on the other hand, birefringence and anisotropy of the optical gain in the plane of growth leads not only to a higher threshold but alsoto a rotation of the optical polarization which is not any more TE- or TM-polarized but influenced by the ordinary and extraordinary refractive index of the material. We observe stimulated emission into a mode which is linearly polarized in extraordinarydirection nearly parallel to the c -axis. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Structural and optical characterization of (11-22) semipolar GaN on m -plane sapphire without low temperature buffer layer

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010
Sung-Nam Lee
Abstract We reported the high quality semipolar (11-22) GaN grown on m-sapphire by using the novel two-step growth method without low temperature GaN or AlN buffer layer. It is found that macroscopic surface morphology of semipolar GaN epilayer was very smooth, while microscopic surface structure was arrowhead-like surface structure toward the direction of [1-21-1]. Anisotropic crystal properties of semipolar GaN/m-sapphire were also observed by two incident directions of X-ray beam. Therefore, we suggested that the anisotropic crystal properties and arrow-head like surface structure would be caused by heteroepitaxial crystallograhpic difference between semipolar GaN and m-sapphire. Additionally, photoluminescence (PL) measurements showed the strong bandedge emission of n-type semipolar GaN without yellow luminescence (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]