Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: ZnO and Relatives II

HL 39.5: Talk

Tuesday, March 27, 2012, 12:30–12:45, EW 202

Raman spectra of ZnO and nitrogen doped ZnO – Tensor elements and additional modes — •Thomas Sander, Christian Reindl, Sebastian Eisermann, Elisabeth A. Zolnowski, Stefan Lautenschläger, Bruno K. Meyer, and Peter J. Klar — I. Physikalisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Gießen

Raman spectra of wurtzite ZnO have been studied intensively in the past. However, some unanswered questions still remain, like the Raman tensor elements, which have not been determined yet and are of fundamental physical interest. Furthermore, ZnO is a promising candidate for potential applications in optics and optoelectronics in the near UV region, if one overcomes the lack of reliable p-type doping. Nitrogen is an acceptor in ZnO. Incorporating N into ZnO leads to several additional modes in Raman spectra whose origins are still controversial.

Wurtzite bulk ZnO substrates and nitrogen doped ZnO thin films grown by CVD were studied by Raman spectroscopy. The phonon spectra were recorded in backscattering geometry at room temperature. The samples were rotated around the axis defined by the 532 nm, polarized excitation laser in different scattering geometries. The results allow one to determine the four tensor elements of ZnO and proof the fundamental selection rules. Furthermore, they will shed light on the origin of the controversially discussed additional Raman modes in the spectra caused by the nitrogen incorporation.