Bonding InGaAsP/ITO/Si Hybrid Laser With ITO as Cathode and Light-Coupling Material

A 1.5-μ.m InGaAsP/ITO/Si hybrid laser with indium tin oxide (ITO) as both a cathode and a light-coupling material is presented. The InGaAsP gain structure with a transparent ITO cathode is flip-chip bonded onto a patterned silicon-on-insulator wafer. The light generated in the InGaAsP multiquantum wells is coupled through the ITO cathode into the Si waveguide to form an InGaAsP/ITO/Si hybrid laser. The threshold current density of this hybrid laser is 20 kA/cm2at 210 K. Due to the advantages of post-bonding and simplicity of the fabrication process, such a hybrid laser may be a promising Si light source.