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Proceedings Paper

Studies of the critical electric field and L valley offset of a semiconductor characterized by terahertz radiation
Author(s): J. S. Hwang; H. C. Lin; C. K. Chang; T. S. Wang; K. L. Lin; L. S. Chang; Y. T. Lu
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Paper Abstract

The amplitudes of terahertz radiation are measured for a series of GaAs surface intrinsic-n+ (SIN+) structures with various built-in surface electric fields as the bias. As the surface field is lower than the so-called "critical electric field" related with the energy difference between the &Ggr; to L valley of the semiconductor, the amplitude is proportional to the product of the surface field and the number of photo-excited carriers. As the intensity of surface field exceeds the critical field, the THz amplitude is independent of the surface field but proportional the number of the photo-excited carriers. Our study proposed two optimal conditions for an SIN+ structure to serve as a THz emitter: the width of its intrinsic layer is nearly equal to the penetration depth of the pump beam, and the intensity of built-in electric field is nearly equal to the critical electric field. Notably, the critical field determined from the THz amplitude under various electric fields provides one way to estimate the &Ggr; to L valley splitting in semiconductors.

Paper Details

Date Published: 1 February 2007
PDF: 8 pages
Proc. SPIE 6472, Terahertz and Gigahertz Electronics and Photonics VI, 647203 (1 February 2007); doi: 10.1117/12.700142
Show Author Affiliations
J. S. Hwang, National Cheng Kung Univ. (Taiwan)
H. C. Lin, National Cheng Kung Univ. (Taiwan)
C. K. Chang, National Cheng Kung Univ. (Taiwan)
T. S. Wang, National Cheng Kung Univ. (Taiwan)
K. L. Lin, National Cheng Kung Univ. (Taiwan)
L. S. Chang, National Cheng Kung Univ. (Taiwan)
Y. T. Lu, National Cheng Kung Univ. (Taiwan)

Published in SPIE Proceedings Vol. 6472:
Terahertz and Gigahertz Electronics and Photonics VI
Kurt J. Linden; Laurence P. Sadwick, Editor(s)

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