Quantum Ring Intersubband Detectors for Terahertz Detection at High Temperatures

Abstract

Abstract : The research was focused on the development of quantum ring intersubband detectors for the 1-3 THz range and demonstration of raster scan imaging with these detectors. Molecular beam epitaxy of relatively small InAs/GaAs quantum dots and their subsequent transformation to quantum rings by post-epitaxy thermal annealing was investigated. Photoconductive detectors with multiple quantum ring layers in the active region and a single barrier at the end of the heterostructure exhibited very low dark current density. The rings have a single bound state and emission of photoexcited carriers gives rise to a spectral response peaking at 1.82 THz (165 m) at 5.2 K. The peak responsivity is 25 A/W. Raster scan imaging was also investigated with the detectors where a seven segment display and an incandescent light bulb filament were imaged in the 1-3 THz range.