Intraband absorption in InAs/GaAs quantum dot infrared photodetectors - Effective mass versus k × p modelling

Theoretical modelling of the intraband absorption spectrum in InAs/GaAs quantum dot infrared photodetectors is performed for several typical structures reported in the literature. The calculations are performed within the framework of the two methods: a simple and so far widely used effective mass method with the values of conduction band offset and the effective mass modified to take account of the effects of strain and band mixing on average and the more realistic eight-band k × p method with the strain distribution taken into account via the continuum mechanical model. Both methods give qualitatively the same results; however, the peak positions obtained within the effective mass approach are blue shifted and the absorption cross sections are overestimated, compared to the more accurate k × p approach.