Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: Poster I

HL 35.9: Poster

Dienstag, 8. März 2016, 15:00–19:00, Poster A

Time-resolved photoluminescence and spin dynamics of GaSe crystals — •Maike Halbhuber, Philipp Nagler, Christian Schüller, and Tobias Korn — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040, Regensburg, Germany

Gallium Selenide (GaSe) is a layered semiconductor with a direct band gap of about 2.02 eV at room temperature at the Γ-point. Its peculiar band structure allows optical generation and detection of spin polarization. Here, we investigate the emission spectra of GaSe thin films by means of continuous-wave (cw) and time-resolved µ-photoluminescence (PL). Our samples are prepared by mechanical exfoliation from GaSe bulk. In temperature-dependent cw PL measurements we could extract a red-shift of the direct free-exciton recombination energy which can be well explained by a Varshni Fit. The degree of spin polarization showed a strong temperature dependence, resulting in a decrease of the time-averaged spin polarization with increasing temperature. Furthermore we studied the lifetime of the PL and the spin polarization by using a streak camera system. Thereby we see dependencies of the spin polarization on both temperature and excitation wavelength. By applying an in-plane magnetic field we observe precession of the spin polarization which enables the determination of the g-factor of GaSe.