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HL: Fachverband Halbleiterphysik

HL 75: Poster IIIB

HL 75.3: Poster

Donnerstag, 19. März 2020, 15:00–17:30, P2/3OG

Raman spectroscopy on anisotropic media — •Ron Hildebrandt¹, Chris Sturm¹, Matthias Wieneke², Armin Dadgar², and Marius Grundmann¹ — ¹Universität Leipzig, Felix Bloch Institute for Solid State Physics, Germany — ²Otto-von-Guericke Universität Magdeburg, Institute for Physics, Germany

Raman spectroscopy is a widely used technique e.g. for the determination of the phonon modes, alloy composition, crystalline orientation or characterization of crystalline quality. In optically anisotropic materials, the polarization of the incident and scattered light changes along the propagation within the crystal due to birefringence. Thus the "standard" Raman tensor formalism cannot be applied there. Recently we presented a modified Raman tensor formalism which allows to model the Raman intensity in dependence on the polarization configuration for any crystal symmetry [1,2]. For an optically uniaxial crystal with the optical axis in the surface plane, the effective standard Raman formalism is recovered except an additional phase factor needs to be added to the Raman tensor elements. This phase factor depends only on the material’s birefringence and the penetration depth.

Here we investigated exemplarily on a-plane GaN the phase factor as a function of the penetration depth by varying the film thickness from 0.7 to 12 µm. The experimentally determined phase factors agree very well with predictions by the modified Raman formalism.

[1] C. Kranert et al., Phys. Rev. Lett., 116, 127401, 2016.

[2] C. Kranert et al., Sci. Rep., 6, 35964, 2016.