High performance single emitter homojunction interfacial workfunction far infrared detectors 

 D. G. Esaev, M. B. M.  Rinzan, S. G. Matsik, and A. G. U. Perera

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

 H. C. Liu

Institute for Microstructural Sciences,

National Research Council, Ottawa K1A 0R6, Canada

 B. N. Zvonkov and V. I. Gavrilenko

Institute for Physics of Microstructures, Nizhny Novgorod, Russia

 A. A. Belyanin

Department of Physics,

Texas A & M University, College Station, TX 77843 

ABSTRACT

Results are reported on p-GaAs Homojunction Interfacial Workfunction Internal Photoemission Far Infrared (HIWIP FIR) detectors with a  ~ 10¹⁹ cm^-3 carbon doped single emitter and a barrier layer for three different barrier thicknesses. A remarkably high quantum efficiency with low dark current and an increased responsivity were observed for devices with 1, 0.1, and 4 mm thick barrier regions. The dark current densities for these structures are the order of 1-10 mA/cm² at 4.2 K, corresponding to a high dynamic resistance compared with previous HIWIP FIR detectors. A detector with a barrier thickness of 1 mm had a peak responsivity of 18.6 A/W, a peak detectivity D* = 9 x 10¹¹ cm Hz^1/2/W, and a quantum efficiency of 40% at a wavelength of 58 mm under a reverse bias measured at 4.2 K. Cutoff wavelengths of these detectors vary with bias and are around 70 mm as expected. The main features of the absorption and responsivity spectra are well described based on a model incorporating free carrier absorption, hot hole transport, and emission over the barrier. 

PACS:78.20.Bh, 78.66.Fd, 85.60.Gz

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