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Proceedings Paper

Terahertz emission from narrow band gap semiconductors
Author(s): Ingrid Wilke
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Paper Abstract

We report an experimental study on THz-emission from narrow band gap semiconductors excited by femtosecond nearinfrared laser pulses. In particular, we studied GaSb, Ga1-xInxSb and InN. The Ga1-xInxSb material system enables the study of the influence of carrier concentrations on THz emission process in narrow band gap semiconductors. The study demonstrates the existence of a compromise between the positive effect of high electron temperature provided by narrow band gap materials and the negative effect of high intrinsic carrier concentrations. The influence of the majority and minority carrier types and concentrations on THz emission strength was investigated using GaSb:Te. By varying the majority and minority carrier type and carrier concentrations over three orders of magnitude the THz emission mechanism in GaSb can be tuned from being dominated by the photo-Dember effect to being dominated by surface field acceleration. Within each regime photo-Dember based THz emission and surface field acceleration based THz emission are maximized under specific majority and minority carrier concentrations. Strong advantages of InN as THz-emitter over other narrow band gap materials, are strong intrinsic electric fields, low intrinsic carrier concentration and most importantly, very low probability of intervalley scattering.

Paper Details

Date Published: 26 September 2007
PDF: 9 pages
Proc. SPIE 6772, Terahertz Physics, Devices, and Systems II, 67720N (26 September 2007); doi: 10.1117/12.735101
Show Author Affiliations
Ingrid Wilke, Rensselaer Polytechnic Institute (United States)

Published in SPIE Proceedings Vol. 6772:
Terahertz Physics, Devices, and Systems II
Mehdi Anwar; Anthony J. DeMaria; Michael S. Shur, Editor(s)

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