  Metal-halide perovskites are promising lasing materials for realization of
monolithically integrated laser sources, the key components of silicon photonic
integrated circuits (PICs). Perovskites can be deposited from solution and
require only low temperature processing leading to significant cost reduction
and enabling new PIC architectures compared to state-of-the-art lasers realized
through costly and inefficient hybrid integration of III-V semiconductors.
Until now however, due to the chemical sensitivity of perovskites, no
microfabrication process based on optical lithography and therefore on existing
semiconductor manufacturing infrastructure has been established. Here, the
first methylammonium lead iodide perovskite micro-disc lasers monolithically
integrated into silicon nitride PICs by such a top-down process is presented.
The lasers show a record low lasing threshold of 4.7 ${\mu}$Jcm$^{-2}$ at room
temperature for monolithically integrated lasers, which are CMOS compatible and
can be integrated in the back-end-of-line (BEOL) processes.
