A spectroscopic study of GaAs homojunction internal photoemission far-infrared detectors

W. Z. Shen, A. G. U. Perera, S. K. Gamage and H. X. Yuan
Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303

H. C. Liu and M. Buchanan
Institute for Microstructural Sciences, National Research Council, Ottawa, Canada K1A OR6

W. J. Schaff
School of Electrical Engineering, Cornell University, Ithaca, NY 14853

ABSTRACT
We report a spectroscopic study of absorption and photoconductivity in GaAs homojunction interfacial workfunction internal photoemission (HIWIP) far-infrared (FIR) detectors utilizing molecular beam epitaxy (MBE) grown multilayer (p⁺-p^--p⁺-p^-...)structures. Strong FIR (50-200 pm) free carrier absorption has been observed and analyzed for a p⁺ GaAs thin film, revealing the suitability for FIR detectors has been determined to be an acoustic phonon-emission assisted process. A simple recombination model is proposed to account for the bias dependence of the responsivity and the saturation behavior. Using the measured responsivity and dark current data, detectivity (D_lambda) of the FIR detectors has also been estimated. © 1997 Elsevier Science B. V. All rights reserved.

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