Silicon photonics (SiPh) is an important technology in the fields of semico
nductor and optoelectronics. By manufacturing SiPh chips in modern CM
OS foundries, the powerful, cost-effective, and functional SiPh chips could

have a wide range of applications including optical communications, bio-
medical detection, and quantum-computing. However, the current bottle

neck of SiPh is the lack of efficient on-chip lasers due to the indirect-band
gap nature of group-IV semiconductors, limiting the further development
of SiPh. Thus, it is extremely to break the fundamental limitation to create
on-chip SiPh lasers.
Here we demonstrate CMOS-compatible, monolithically-integrated group
-IV lasers on silicon as the important on-chip lasers for silicon photonics.
Using low-temperature growth technique and Ge buffer layer technique,
we successfully grew high-Sn-contnet GeSn layers with a direct bandgap
on silicon substrates. By processing the grown sample into laser cavities,
we achieved lasing action under optical pumping. The threshold of our Ge
Sn lasers is relative lower compared to the results from other group in the
world, and is comparable with III-V lasers. With the CMOS-compatibility, t
his technology could be used as the on-chip laser light sources for SiPh, e
nabling stronger and functional SiPh chips for a wide range of application
s.