Novel III-V/Si hybrid laser structures with current injection across conductive wafer-bonded heterointerfaces: A proposal and analysis

We propose two novel III-V/Si hybrid laser structures with patterned window arrays in metal thin film wafer-bonding layers. The metal-mediated bonded III-V/Si heterointerface exhibits high electrical and thermal conductivity while allowing optical coupling between the III-V gain layer and the underneath Si waveguide through the openings in the metal bonding layer. We numerically examine the validity of the proposed hybrid laser structures through calculations of their modal propagation loss by metal's absorption and threshold current densities. We also propose another hybrid laser structure utilizing conductive direct semiconductor/semiconductor wafer bonding exploiting a spatial gain profile well overlapped with the waveguide mode and no metal-induced loss relative to those metal-mediated-bonded. All of these three structures have advantages such as spontaneous lateral current confinement and simpler fabrication over conventional oxide-mediated-bonded hybrid lasers.