Infrared detector based on modulation-doped quantum-dot structures

We investigate a detector model, where quantum dots are surrounded by potential barriers created by modulation doping. Strong separation of the localized ground states and continuum conducting states drastically increases the photoelectron capture time. At room temperatures the photoelectron capture is conditioned by electron diffusion in the potential relief. Monte-Carlo modeling with diffusion-limited capture in the modulation-doped quantum-dot structures is used to calculate carrier lifetime and photoconductive gain as functions of the electric field. We evaluate the photodetector characteristics and show that photoconductive gain is substantially improved due to longer lifetimes of photoelectrons. Optimized quantum-dot structures have a strong potential for development IR room-temperature detectors.