By Pallab Bhattacharya, Fellow IEEE, Xiaohua Su, G. Ariyawansa, and A. G. U. Perera
ABSTRACT
Quantum-dot infrared photodetectors have emerged as attractive devices for sensing long wavelengthradiation. Their principle of operation is based on absorption of radiation via intersublevel transitions in quantum dots. Multiple layers of self-organized In(Ga)As/Ga(Al)As quantum dots are generally incorporated in the active region of these devices. Three-dimensional quantum confinement allows normal incidence operation. This paper describes a novel variation in the design of these devices which allows a significant reduction of the dark current, high temperature operation and extension of operation to terahertz frequencies. The principle of operation and operating characteristics of this deviceVthe tunnel quantum-dot intersublevel detectorVare described. Operation is demonstrated from 6–80 m at temperatures up to 300 K with acceptable values of peak responsivity (0.1–0.75 A/W) and specific detectivity (107–1011 cm Hz1=2=W1, depending on temperature and wavelength).
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