Interface roughness scattering in InGaAs/InAlAs double quantum wells grown on (100) and (411)A InP substrates at different growth temperatures

Reduced interface roughness scattering in InGaAs/InAlAs quantum cascade lasers grown on (411)A InP substrates

“…The (411)A orientation is known to allow higher electron mobility and narrower photoluminescence in quantum wells (QWs). [24][25][26] Our own results on InGaAs/InAlAs double-QW structures lattice-matched to InP have confirmed a marked increase in the electron mobility in (411)A oriented samples 27 and have inspired us to investigate if a reduced intrasubband scattering seen in transport translates into a reduction in intersubband scattering that is detrimental to QCL operation. In this letter, we compare the intersubband scattering due to IFR scattering in lattice-matched QCLs grown on (411)A to (100) InP substrates.…”

“…This study was motivated by the observed difference in intrasubband IFR scattering between (100) and (411) oriented structures, resulting in the (411) structures having much higher electron mobility than (100) structures. 27 In that study, a double QW structure was used to increase the overlap of the electronic wavefunction with the interface in order to emphasize the IFR scattering. Those structures were much higher doped than QCL structures-about 1 Â 10 12 cm À2 , resulting in a relatively large Fermi wavevector k F .…”