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HL: Halbleiterphysik
HL 63: Ultrakurzzeitph
änomene
HL 63.7: Vortrag
Mittwoch, 9. März 2005, 12:15–12:30, TU P-N201
Terahertz microscopy of charge carrier distributions — •F. F. Buersgens1, H.-T. Chen2, and R. Kersting1,2 — 1Physics Department, University of Munich, 80799 Munich, Germany — 2Department of Physics, Rensselaer Polytechnic Institute, Troy, NY 12180, U.S.A.
Our recent development of an apertureless THz scanning near-field optical microscope (THz-SNOM) allows for submicron spatial resolutions and suggests a broad variety of novel applications in semiconductor technology [1,2]. For example, this technique may be used for the detection of charge carrier distributions in a field effect transistor or for the contactless characterization of nano-electronic building blocks. In this contribution we will demonstrate that apertureless THz-microscopy can be used to detect electron distributions on a microscopic scale. The basic mechanism is that a metallic probe allows to map the THz permittivity of the surface, which depends on the electron density in the region under the probing tip. By applying a potential between the needle and the semiconductor the electron density can be locally controlled. We show first evidence that THz microscopy is capable to detect electron populations in n-doped GaAs structures that consist only of about 1000 electrons.
[1] H.-T. Chen et al. Appl. Phys. Lett. 83, 3009 (2003)
[2] H.-T. Chen et al. Phys. Rev. Lett. in press (2004)