Long wavelength infrared (LWIR) photodetection in a modulation doped thyristor

► A LWIR intersubband photodetector operating as a thyristor is described. ► The potential benefits are uncooled operation and monolithic read-out circuits. ► The nonlinear response upon power results from the depletion of QW carriers. ► The operating parameters are determined in the range of 0.1 μW – 10 mW/cm2. A modulation doped thyristor concept is described for LWIR photodetection based upon intersubband bound to continuum absorption. The intersubband absorption generates photocurrent from undoped quantum wells to modulation doped layers (MDL). Due to the lower dark current compared to conventional quantum well infrared photodetectors (QWIPs), the thyristor infrared detector operates with little or no cooling and with similar or better performance than QWIPs at low temperatures. The operating characteristics of absorption coefficient, quantum efficiency, responsivity, detectivity, infrared gain, and dark current are determined as a function of thyristor voltage and input power level in the range of 1 μW/cm 2.