Published online by Cambridge University Press: 15 February 2011
Multiple layers of self assembled In0.3Ga0.7As quantum dots of different size were grown on GaAs (100) using molecular beam epitaxy. Fourier-transform infrared spectroscopy shows absorption in the long-wavelength infrared region (8–10 νm) under normal incidence. The absorbance peak shift with dot size was investigated and revealed non-monotonic behavior of intersubband transitions. The optical absorption coefficient was calculated to be in order of 3.8×103 cm-2.