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

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 degrees C) Pd-mediated wafer bonding process. A low interfacial resistivity of only 0.2 Omega cm(2) 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 J(th) and differential quantum efficiency eta(d) of 240 A/cm(2) and 23.9%, respectively, at room temperature are obtained with laser bars of cavity length and waveguide ridge of 1.5 mm and 5 mu m, respectively. The InAs QD lasers also show operation up to 100 degrees C with a threshold current density J(th) and differential quantum efficiency eta(d) of 950 A/cm(2) and 9.3%, respectively. The temperature coefficient T-0 of 69K from 60 to 100 degrees C is characterized from the temperature dependent Jth measurements. (C) 2015 AIP Publishing LLC.