GaAs/InGaAs quantum well infrared photodetector with a cutoff wavelength at 35 µm

A. G. U. Perera, and G. Matsik,

Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303

H. C. Liu, M. Gao and M. Buchanan

Institute for Microstructural Sciences, National Research Council, Ottawa KIA 0R6, Canada

S. W. J. Schaff and W. Yeo

School of Electrical Engineering, Cornell University, Ithaca, New York 14853

ABSTRACT

GaAs/InGaAs far-infrared quantum well photodetectors based on a bound-to-continuum intersubband transition with a (zero response) cutoff wavelength of 35 µm and a responsivity of 0.45 A/W and detectivity of 6.0 × 10⁹ cm /W at a wavelength of 31 µm and a temperature of 4.2 K have been experimentally achieved. Infrared response was observed at temperatures up to 18K. A calculated responsivity spectrum using a bound-to-continuum line shape corrected for phonon absorption is fitted to the experimental response. The calculated line shape without absorption gives a cutoff wavelength of 38 µm with a peak responsivity of 0.50 A/W and a directivity of 6.6 × 10⁹ cm /W at 32 µm.

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