35 μm cutoff bound-to-quasibound and bound-to-continuum InGaAs QWIPs

Abstract GaAs/InGaAs far-infrared quantum well photodetectors based on a bound-to-continuum (bc) and bound-to-quasibound (bq) intersubband transition with a cutoff wavelength (zero response) up to 35 μm are reported. A peak responsivity of 0.45 and 0.30 A/W and detectivity of 6×10 9 and 1.0×10 10 cm Hz /W at a wavelength of 31 μm and a temperature of 4.2 K respectively for a bc and a bq detector have been achieved.