Silicon photonics has been demonstrated for most optical functions, including waveguides, resonators and switches, but optical emitters has remained a task for III-V materials using gallium, arsenide, indium and their various nitrides.
Now, Akihiro Wakahara, the project team leader at Toyohashi Tech (Aichi, Japan) and colleagues claim to have invented a method of mitigating the lattice mismatch between silicon and III-V materials, thereby enabling optical emitters—including lasers—to be fabricated on silicon chips.
As a demonstration, Wakahara's team constructed a one-bit opto-electronic counter circuit that combines silicon field effect transistors (FETs) alongside gallium phosphide nitride (GaPN) LEDs on a single chip. The key to solving the lattice mismatch between silicon and III-V was accomplished by growing a thin gallium phosphide (GaP) layer using migration-enhanced epitaxy with III–V–N alloys. The resulting lattice matched Si/GaPN/Si hetero-structures were grown on silicon substrates using dual-chamber molecular beam epitaxy (MBE).