1305 nm Few-Layer MoTe2-on-Silicon Laser-Like Emission

The missing piece in the jigsaw of silicon photonics is a light source that can be easily incorporated into the standard silicon fabrication process. Here, silicon laser-like emission is reported that employs few-layer semiconducting transition metal dichalogenides of molybdenum ditelluride (MoTe2) as a gain material in a silicon photonic crystal L3 nanocavity. An optically pumped MoTe2-on-silicon laser-like emission at 1305 nm, i.e. in the center of the “O-band” of optical communications, is demonstrated at room temperature and with a threshold power density of 1.5 kW/cm2. The surprising insight is that, contrary to common understanding, a monolayer MoTe2 is not required to achieve higher efficiency laser-like operation. Instead, few-layer MoTe2 offers a higher overlap between the two dimensional (2D) gain material and the optical mode for sufficient gain. The ability to use few-layer material opens new opportunities for deploying manufacturing methods such as chemical vapor deposition and thereby brings 2D-on-silicon devices a step closer to becoming a scalable technology.