Substrate-orientation dependence of lasing properties in quantum well lasers

In a zinc blende type crystal like GaAs, there exists an asymmetry in the energy bands. Because of such asymmetry, the optical properties in quantum wells (QWs) depend on the substrate-orientation on which the QW structures are grown. However, in most theoretical and experimental work to date, QW lasers grown on (100)-oriented substrates have been studied.1,2 Pioneering experimental work which was done by Hayakawa et al.3 demonstrated that lower threshold currents can be achieved in the QW laser grown on (11 l)-substrates.