Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 89: Optical Properties II
HL 89.9: Vortrag
Freitag, 18. März 2011, 12:30–12:45, POT 251
Nanoscale Optical Imaging of Semiconductor Nanowires — •Miriam Böhmler1, Anton Myalitsin2, Alf Mews2, and Achim Hartschuh1 — 1Department Chemie & CeNS, Ludwig-Maximilians-Universität München — 2Department Chemie, Universität Hamburg
Inorganic semiconducting nanowires (NWs) feature size-related optical properties which make them interesting for a wide range of applications, e.g. nanoscale optoelectronics, sensors, and photovoltaics. Their relevant length scales that are determined by nanowire diameter and exciton Bohr radius, however, can not be resolved by conventional diffraction limited methods.
We illustrate the prospects of tip-enhanced near-field optical microscopy (TENOM) [1] as a method to investigate single nanowires. In TENOM a sharp metallic tip acts as optical antenna thereby enhancing the detected signal and increasing the optical resolution to about 15 nm. We present our investigations of CdSe NWs which have been grown by the wet chemical solution liquid solid technique [2]. Here, TENOM provides the possibility to simultaneously image photoluminescence (PL) as well as Raman scattering of individual NWs with nanoscale resolution. We observe spatial variations of the PL intensity and energy on a length scale of about 15 nm indicating crystal phase transitions and diameter fluctuations.
[1] A. Hartschuh, "Tip-enhanced near-field optical microscopy", Angew. Chemie (Int. Edition) 47, 8178 (2008). [2] Z. Li, et.al., "Controlled Synthesis of CdSe Nanowires by Solution-Liquid-Solid Method", Adv. Funct. Mater. 19, 3650-3661 (2009).