Mid- and far-infrared intersubband absorption in quantum dash nanostructures

The authors calculate and analyze intersubband absorption in InAs/GaAs quantum dash ensemble. The absorption spectrum dominantly occupies the mid- and extends to the far-infrared region. As far as the wetting layer is taken into account, the electron concentration significantly affects the absorption and the spectrum can be tailored by adjusting spacer layers. It is shown that size fluctuation of dashes causes spectrum broadening and its asymmetry, while the increase in the wetting layer thickness leads to a redshift in the spectrum and decrease in the absorption. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3486165]