Toward Thin‐Film Laser Diodes with Metal Halide Perovskites

Abstract Metal halide perovskite semiconductors hold a strong promise for enabling thin‐film laser diodes. Perovskites distinguish themselves from other non‐epitaxial media primarily through their ability to maintain performance at high current densities, which is a critical requirement for achieving injection lasing. Coming in a wide range of varieties, numerous perovskites delivered low‐threshold optical amplified spontaneous emission and optically pumped lasing when combined with a suitable optical cavity. A progression toward electrically pumped lasing requires the development of efficient light‐emitting structures with reduced optical losses and high radiative efficiency at lasing‐level current densities. This involves a set of important trade‐offs in terms of material choice, stack and waveguide design, as well as resonator integration. In this Perspective, the key milestones are highlighted that have been achieved in the study of passive optical waveguides and light‐emitting diodes, and these learnings are translated toward more complex laser diode architectures. Finally, a novel resonator integration route is proposed that is capable of relaxing optical and electrical design constraints.