Low-threshold continuous-wave operation of an oxide-confined vertical-cavity surface-emitting laser based on a quantum dot active region and half-wave cavity

We describe the first room-temperature continuous-wave (CW) lasing characteristics of a QD active region placed in an oxide-confined half-wave vertical-cavity surface-emitting laser (VCSEL) structure. We have maintained nearly the same cavity design as used with an InGaAs QW by choosing the active material as In/sub 0.50/Ga/sub 0.35/Al/sub 0.15/As to generate QD emission centered around 0.97 /spl mu/m. Light versus current curves are shown for a 7 /spl mu/m, a 3 /spl mu/m and a 1.5 /spl mu/m square QD VCSEL, CW at room-temperature. The lowest threshold current is 235 /spl mu/A for the 7 /spl mu/m device which yields a threshold current density of /spl sim/480 A/cm2. This is lower than for QD room-temperature lasers reported elsewhere. The 3 /spl mu/m and 1.5 /spl mu/m have increasingly higher thresholds of 435 /spl mu/A and 1.14 mA. The electroluminescence is also shown from a 7 /spl mu/m VCSEL device before the deposition of any upper MgF/ZnSe pairs with the lasing spectra from the 7 /spl mu/m VCSEL overlaid.