On the linewidths of intersubband transitions on GaAs-Al xGa 1−xAs quantum wells in electric field

Abstract

In this paper influence of single broadening mechanisms on intraband absorption line profile in quantum wells id analysed. The expression for the line profile arising only from the combined influence of the effective-mass-mismatch and the material nonparabolicity is derived, the later beng responsible for an increase of the total linewidth by a factor of (2÷3). The full line profile in GaAs-Al xGa 1−xAs system is shown to be asymmetric and red-shifted, due to the above effects. Numerical results, given for a GaAs well in Al 0.4Ga 0.6As bulk indicate that there are regions of structure parameters where some of broadening mechanisms play a dominant role.