Multicolor charge-sensitive infrared phototransistor (CSIP)

Controllable detection at several wavelengths is highly desired in all the sensors of radiation. The demand is especially strong for gaining richer information in the imaging application of charge-sensitive infrared phototransistors (CSIPs). For this purpose, a multicolor CSIP is designed and demonstrated in this work by introducing multiple photo-floating gates. An unprecedentedly broad detection band, covering wavelength range of 8~17 um (17.6~37.5 THz), has been achieved with a quadruple QW structure. Detailed mechanism of the multicolor detection and tuning of the spectral band in terms of gate biasing will be discussed.