Preparation of 1.78hyphen;mgr;m wavelength Al0.2Ga0.8Sb/GaSb doublehyphen;heterostructure lasers by molecular beam epitaxy

摘要

As the losses due to Rayleigh scattering decrease at a rate of lgr;4with increasing wavelength lgr;, the future generation of optical fibers, light sources, and detectors may well be operating at still longer wavelength beyond 1.55 mgr;m. The present letter reports the first preparation of Al0.2Ga0.8Sb/GaSb doublehyphen;heterostructure (DH) lasers by molecular beam epitaxy (MBE) operating at 1.78 mgr;m. For AlxGa1minus;xSb withxlsim;0.1, roomhyphen;temperature photoluminescent intensity and linewidth similar to those of bulk GaSb substrate of similar carrier concentration were obtained. The Al0.2Ga0.8Sb/GaSbthinsp;DH laser wafers grown by MBE have smooth, featureless, mirrorhyphen;reflecting surfaces. Reflection highhyphen;energy electron diffraction study shows that the abrupt Al0.2Ga0.8Sb/GaSb interfaces were atomically smooth. Initial threshold current measurements gave a pulsed threshold current density of 3.4 kA/cm2for a diode of 380times;200 mgr;m and an active GaSb layer of 0.33 mgr;m.