High performance InAs quantum dot lasers on silicon substrates by low temperature Pd-GaAs wafer bonding

Abstract

InAs quantum dot (QD) laser heterostructures have been grown by molecular beam epitaxy system on GaAs substrates, and then transferred to silicon substrates by a low temperature (250 °C) Pd-mediated wafer bonding process. A low interfacial resistivity of only 0.2 Ω cm2 formed during the bonding process is characterized by the current-voltage measurements. The InAs QD lasers on Si exhibit comparable characteristics to state-of-the-art QD lasers on silicon substrates, where the threshold current density Jth and differential quantum efficiency ηd of 240 A/cm2 and 23.9%, respectively, at room temperature are obtained with laser bars of cavity length and waveguide ridge of 1.5 mm and 5 μm, respectively. The InAs QD lasers also show operation up to 100 °C with a threshold current density Jth and differential quantum efficiency ηd of 950 A/cm2 and 9.3%, respectively. The temperature coefficient T0 of 69 K from 60 to 100 °C is characterized from the temperature dependent Jth measurements.