Ge-on-Si laser operating at room temperature

TLDR

Monolithic Si lasers are ideal for large‑scale integration, and Ge is a promising candidate because of its pseudodirect gap and CMOS compatibility. The study reports the first experimental observation of room‑temperature lasing from the direct‑gap transition of Ge‑on‑Si in an edge‑emitting waveguide. The authors employed a tensile‑strained, n‑type doped Ge‑on‑Si layer in an edge‑emitting waveguide to achieve lasing. The device shows room‑temperature photoluminescence, electroluminescence, and optical gain with a 1590‑1610 nm spectrum, line narrowing, TE‑polarized emission, and a clear threshold.

Abstract

Monolithic lasers on Si are ideal for high-volume and large-scale electronic-photonic integration. Ge is an interesting candidate owing to its pseudodirect gap properties and compatibility with Si complementary metal oxide semiconductor technology. Recently we have demonstrated room-temperature photoluminescence, electroluminescence, and optical gain from the direct gap transition of band-engineered Ge-on-Si using tensile strain and n-type doping. Here we report what we believe to be the first experimental observation of lasing from the direct gap transition of Ge-on-Si at room temperature using an edge-emitting waveguide device. The emission exhibited a gain spectrum of 1590-1610 nm, line narrowing and polarization evolution from a mixed TE/TM to predominantly TE with increasing gain, and a clear threshold behavior.