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O: Fachverband Oberflächenphysik

O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)

O 60.21: Poster

Wednesday, March 16, 2011, 17:30–21:00, P4

Optical Second-Harmonic Generation at the GaP/Si(001) interface — •Kristina Klass, Johannes Reimann, Gerson Mette, Wolfgang Stolz, Kerstin Volz, and Ulrich Höfer — Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, D-35032 Marburg

Due to similar lattice constants (a=0.54 nm) GaP as a compound semiconductor can be grown on Si without significant lattice mismatch. The combination of Silicon with GaP-based direct III/V semiconductors is of great interest for the realization of optoelectronics based on this well understood substrate. We have employed optical second-harmonic generation (SHG) as a non-invasive and contactless method to characterize the GaP/Si(001) interface. Femtosecond laser pulses are focused on a thin sample which can be rotated around its z-axis. Irradiation and detection of different polarizations as well as variation of the angle of incidence yield access to different tensor elements of the second-order nonlinear susceptibility tensor. The investigated samples show surprisingly strong variation of the SHG response depending on growth condition and the Si(001) substrate structure. In particular, we find a strong 2-fold symmetric SHG-component which is correlated to the presence of double height steps and an almost single-domain Si(001) substrate.