We have demonstrated the operation of a frontside-illuminated quantum-well photodetector based on intersubband absorption in a quantum well (QW) with a targeted peak frequency of . A multiple-quantum-well structure consists of 20 periods of QWs interleaved by barriers with an Al alloy content of 2%. We measured the following performance characteristics: dark current, responsivity, and spectral response. A responsivity of at an electric bias of and an operating temperature of was obtained with a peak response close to the designed detection frequency. The dark current density was a few and was limited by thermally assisted tunneling through the barriers. We looked also at possible designs to optimize the device’s performance.
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