Strong normal-incidence infrared absorption andphoto-current spectrafrom highly uniform (In,Ga)As/GaAs quantum dot structures

The authors report normal-incidence infrared absorption in the wavelength range 12 – 14 µm and low temperature (40 K) photo-current spectra from an (In,Ga)As/GaAs quantum dot structure. The basic structure consists of 20 periods of highly uniform (In,Ga)As/GaAs dot arrays. The strong room temperature absorption indicates the high quality of the superlattice structure; this is considered to be very promising for the fabrication of high performance, long wavelength photodetectors.