Electrically Injected InGaAsP Microdisk Lasers Heterogeneously Integrated on a Si-Wafer

We report on electrically pumped lasing in microdisk cavities etched in a thin InP-based membrane directly bonded on top of a silicon wafer. The microdisks were planarized by means of a benzocyclobutene (BCB) layer, into which contact windows were etched to perform current injection. The top metal contact is placed only in the centre of the disk, whereas the bottom contacting is done by means of a thin lateral InP contacting layer. In order to avoid large optical absorption in p-type contact layers, a tunnel junction was used in combination with two n-type contacts. Lasing was observed in pulsed regime at room temperature with current thresholds in the range 0.55-1.1 mA, for microdisks with a diameter in the range 6-9 mum