Berlin 2012 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 33: Ge/Si II
HL 33.3: Talk
Tuesday, March 27, 2012, 10:00–10:15, EW 015
Probing local strain and composition in Ge nanowires by means of tip-enhanced Raman scattering — •Juan S. Reparaz1,2, Niculina Peica1, Ronny Kirste1, Alejandro R. Goñi2,3, Gordon Callsen1, Markus R. Wagner1, Maria I. Alonso2, Miquel Garriga2, I. Carmen Marcus2, Isabelle Berbezier4, Jannina Maultzsch1, Christian Thomsen1, and Axel Hoffmann1 — 1Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, u o a 10623 Berlin, Germany — 2Institut de Ciència de Materials de Barcelona-CSIC, Esfera UAB, 08193, Bellaterra, Spain — 3ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain — 4IM2NP, CNRS - Univ. Aix Marseille, Campus St. Jèrôme, Case 142, 13397 Marseille Cedex 20, France
In this work we investigate local strain and composition in Ge nanowires using tip-enhanced Raman scattering (TERS). We will mainly focus on the influence of the tip on the NW's Raman spectrum, showing that the electromagnetic field enhancement due to the TERS effect allows to probe the local composition and strain in these nanostructures. A close comparison with what can be achieved using micro-Raman will be discussed, showing the great advantages of TERS over conventional far-field optical techniques. As a striking result we will show the presence of local vibrational modes (LVMs) of the GeGe mode in the presence of a Au rich enviroment which acts as catalyst for the NWs growth, are only observed using TERS. Finally, the dependence of strain and composition with the position along the NWs will be presented.