Two-color quantum well infrared photodetector simultaneously working at 10—14 μm

Abstract

We have demonstrated a two-color quantum well infrared photodetector (QWIP) exhibiting simultaneous photoresponse with cutoff wavelengths at 11.8 and 14.5 μm, respectively. Strong photocurrent signals are observed at temperature of 77 K. The simultaneous two-color photoresponse is achieved by utilizing a simple design by broadening the width of the quantum well and selecting an appropriate doping density. The two peaks are attributed to the intersubband transitions from the ground state to the first excited state (bound state) and to the fifth excited state (continuum state), respectively.