Dark current in GaAs/AlxGa1-xAs quantum well infrared detectors

New formulas are derived to calculate the tunneling and thermionic dark currents in GaAs/Alx Ga1-xAs quantum well infrared detectors. Variation of the dark current (Id) with barrier width and doping density is systematically studied. It is shown that increasing the barrier width and/or decreasing the doping density in the well do not always reduce the dark current. Theoretical variation of Id with bias is compared with experimental data.