title: Terahertz frontside-illuminated quantum-well photodetector.
abstract: We have demonstrated the operation of a frontside-illuminated GaAs/AlGaAs quantum-well photodetector based on intersubband absorption in a quantum well (QW) with a targeted peak frequency of 3 THz. A multiple-quantum-well structure consists of 20 periods of 18 nm QWs interleaved by 80 nm barriers with an Al alloy content of 2%. We measured the following performance characteristics: dark current, responsivity, and spectral response. A responsivity of 13 mA/W at an electric bias of 40 mV and an operating temperature of 3 K was obtained with a peak response close to the designed detection frequency. The dark current density was a few microA/cm2 and was limited by thermally assisted tunneling through the barriers. We looked also at possible designs to optimize the device's performance.
authors.affiliation: National Institute of Information and Communications Technology, 4-2-1 Nukui-Kitamachi, Koganei, Tokyo 184-0015, Japan. mikhail@nict.go.jp
authors.forename: Mikhail
authors.initials: M
authors.lastname: Patrashin
authors.forename: Iwao
authors.initials: I
authors.lastname: Hosako