Dilute nitride based double-barrier quantum wells for intersubband absorption at 1.31 and1.55 μm

Abstract

A systematic investigation of intersubband optical absorptions in ${\text{In}}_{x}{\text{Ga}}_{1\ensuremath{-}x}{\text{As}}_{1\ensuremath{-}y}{\text{N}}_{y}/\text{AlAs}/{\text{Al}}_{z}{\text{Ga}}_{1\ensuremath{-}z}\text{As}$ double-barrier quantum well (DBQW) structures is reported. Electron subbands and the energy dependent effective potential for the envelope wave functions are calculated by means of the ten-band $k\ensuremath{\cdot}p$ scheme, which takes into account the effects of subband nonparabolicity and strain. From the calculations of the energy dispersions and wave functions of the respective states, we find that when the conduction-band offset is very large such that the first excited state lies above the localized nitrogen level, each of the ground and the first excited states is split into two levels. The intersubband absorptions in the DBQW structure have been studied by varying the well width and the compositions of the alloys. The strongest calculated absorption peak corresponding to the transition from the ground level to the higher excited level shows the same peculiarities. Finally, DBQW structures, which correspond to 1.31 and $1.55\text{ }\ensuremath{\mu}\text{m}$ intersubband absorptions, respectively, have been achieved.