Room-Temperature Optically Pumped (Al)GaSb Vertical-Cavity Surface-Emitting Laser Monolithically Grown on an Si(1 0 0) Substrate

We report a monolithic vertical-cavity surface-emitting laser (VCSEL) on an Si(0 0 1) substrate operating under room-temperature optically pumped conditions. The GaSb multi-quantum well active region in an Al(Ga)Sb half-wave cavity spacer layer is embedded in AlSb/AlGaSb distributed Bragg reflectors. The 13% lattice mismatch is accommodated by a self-assembled two-dimensional array of 90deg interfacial misfit dislocations resulting in spontaneously relaxed (~98%) and very low defect density (~106/cm2) epilayers. The material characterization is conducted through atomic force microscopy, transmission electron microscopy, and etch-pit density studies. The VCSEL characterization includes lasing spectra and light-in versus light-out curves. A 3-mm pump spot size results in peak threshold excitation density of Ith=0.1 mJ/cm2and a multimode lasing spectrum peak at 1.62 mum. The average output power measured from the device is 25 muW at 1.6Ith