Doping effect on dark currents in In₀.₅Ga₀.₅As∕GaAs quantum dot infrared photodetectors grown by metal-organic chemical vapor deposition

Stacked self-assembled In₀.₅Ga₀.₅As∕GaAs quantum dot infrared photodetectors grown by low-pressure metal-organic chemical vapor deposition, with and without silicon dopants in the quantum dot layers, are investigated. The increase of dark currents observed at higher doping levels is attributed to higher defect density leading to stronger sequential resonant tunneling and to lowering of the operating temperature of the device.