Studies of the critical electric field and L valley offset of a semiconductor characterized by terahertz radiation

J. S. Hwang, H. C. Lin, C. K. Chang, T. S. Wang, K. I. Lin, L. S. Chang, Yan-Ten Lu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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 Γ 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 Γ to L valley splitting in semiconductors.

Original languageEnglish
Title of host publicationTerahertz and Gigahertz Electronics and Photonics VI
DOIs
Publication statusPublished - 2007 May 23
EventTerahertz and Gigahertz Electronics and Photonics VI - San Jose, CA, United States
Duration: 2007 Jan 212007 Jan 22

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6472
ISSN (Print)0277-786X

Other

OtherTerahertz and Gigahertz Electronics and Photonics VI
CountryUnited States
CitySan Jose, CA
Period07-01-2107-01-22

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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