STRAINED-LAYER 1.5pm WAVELENGTH InGaAs/lnP MULTIPLE QUANTUM WELL LASERS GROWN BY CHEMICAL BEAM EPITAXY

A substantial reduction is reported in the threshold current densities for 1 5 p m wavelength In,Ga,+,As/ In,Ga, .,As, -”P, strained-layer multiple quantum well (SLMQW) lasers over lattice-matched MQW lasers. Threshold current density was found to depend sensitively on the InAs content x and thickness d of the In,Ga, -.As quantum wells. Threshold current densities as low as 370A/cm2 and internal quantum efliciency of 90% were obtained for separate confinement heterostructure SL-MQW lasers having four quantum wells and with x = 0.65 and d = 5nm. Such a threshold current density is among the lowest values obtained thus far for 1.5pm wavelength InGaAs/lnCaAsP MQW lasers. The present lasers were grown by chemical beam epitaxy.