Resonant Tunneling Barriers in Quantum Dots-in-a-Well Infrared Photodetectors

The use of resonant tunneling (RT) barriers in the design of quantum dots-in-a-well (DWELL) infrared photodetectors is reported. The design of RT barriers for a variety of goals has been discussed. For simple DWELL designs, we demonstrate 2-3 orders-of-magnitude reduction in the dark current, with significant increase in the specific detectivity (D ^*) of the device. Two RT barriers are designed to selectively extract midwave and longwave components of the spectral response. We also report the use of RT barriers on strain-optimized quantum dots-in-a-double-well (DDWELL) structures to achieve very low dark current levels with peak D ^* of 2.9 ×10¹⁰ cm· Hz^1/2 /W for a longwave infrared detection. Ability to select a particular wavelength in the spectral response is demonstrated with DDWELL architectures as well.