InAs/GaAs Quantum Dot Infrared Photodetector (QDIP) With Double Al0.3Ga0.7As Blocking Barriers

Abstract

The ten stacked self-assembled InAs/GaAs quantum dot infrared photodetectors (QDIP) with different Al Ga As barrier widths and growth temperatures were prepared. Asym- metric current-voltage ( - ) characteristics and 2 7.5 m de- tection window were observed. Peak responsivity of 84 mA/W at 0.4 V and peak specific detectivity of 2.5 10 cm-Hz /W at zero bias were observed at 50 K. The characteristics of polarization insensitivity over the incident light and the high background pho- tocurrent suggest that the self-assembled QDIP can be operated at higher temperature ( 250 K) under normal incidence condition in contrast to quantum well infrared photodetector (QWIP). Index Terms—Infrared photodetector, molecular beam epitaxy, quantum dot.