Tunneling Quantum Dot Sensors for Multi-band Infrared and Terahertz Radiation Detection

Tunneling quantum dot infrared photodetector (T-QDIP) structures designed for multi-band infrared and terahertz radiation detection are demonstrated. In T-QDIP structures, photoabsorption takes place in InGaAs QDs (due to transition of carriers from the QD ground-state to a QD excited-state) and photoexcited carriers are selectively collected by resonant tunneling, while the dark current is blocked by AlGaAs/InGaAs tunneling barriers. This approach was effectively used to develop terahertz sensors. Characteristics of a room temperature T-QDIP showing two color responses at wavelengths of 6 and 17 mum and a terahertz T-QDIP responding at 6 THz are presented.