Conduction intersubband (In,Ga)As/GaAs quantum dot infrared photodetectors

摘要

The authors report a 40-period (In,Ga)As/GaAs normal-incidence quantum dot infrared photodetector operating in the wavelength range 8-14 /spl mu/m. A primary intersubband transition peak is observed at a wavelength of 12.5 /spl mu/m (E/sub 0//spl rarr/E/sub 1/), and a secondary peak at 11.3 /spl mu/m (E/sub 0//spl rarr/E/sub 2/). The measured intersubband energy spacing is in good agreement with calculations. The normal-incidence peak responsivity at the bias voltage of -6 V is /spl sim/0.17 A/W. The background-limited performance temperature of our devices is found to be 62 K.