Photovoltaic quantum-dot infrared detectors

We demonstrate the operation of photovoltaic quantum-dot infrared detectors fabricated from (In, Ga)As/GaAs heterostructures. These detectors are sensitive to normal incidence light. At zero bias, we obtain a low-temperature (78 K) peak detectivity of 2x10(8) cm Hz(1/2)/W, with a responsivity of 1 mA/W at a wavelength of 13 mu m for one of the devices. The photovoltaic effect in our detectors is a result of the intrinsic inversion asymmetry of the band structure of self-formed quantum dots. A compensation voltage of 18 mV is measured. (C) 2000 American Institute of Physics. [S0003-6951(00)01222-5].