Voltage Tunable Multicolor GaAs/AlGaAs Coupled Quantum Well Infrared Photodetector

Tunable quantum well infrared photodetectors (QWIP) has attracted attention because of the mature growth technique of GaAs/AlGaAs quantum wells and their diverse applications such as remote temperature sensing, chemical analysis, military applications, and so on. We have designed, grown, and characterized a voltage tunable multicolor QWIP for the long wavelength infrared detection (7.5 -- 12.4 $\mu $m). The QWIP structure was grown by MBE, and the device is designed to have bound to bound and bound to quasi-continuum transitions in an asymmetrically doped double quantum well. At zero bias we observed several distinctive spectral lines in photoresponse. The device demonstrates strong dependence on a magnitude and a polarity of the bias that is confirmed by the shift of energy levels in the electric field calculated by nextnano$^{3 }$software. In particular, switching bias from +3V to -5V we change the photoresponse of our detector from 8.39 $\mu $m to 10.21 $\mu $m.