Electrostatic epitaxy of orientational perovskites for microlasers.

Orientational growth of single-crystalline structures is pivotal in semiconductor industry, which is achievable by epitaxy for producing thin films, heterostructures, quantum wells and superlattices. Beyond silicon and III-V semiconductors, solution-processible semiconductors, such as metal-halide perovskites, are emerging for scalable and cost-effective manufacture of optoelectronic devices, whereas the polycrystalline nature of fabricated structures restricts their application towards integrated devices. Here, we develop electrostatic epitaxy, a process sustained by strong electrostatic interactions between self-assembled surfactants (octanoate anions) and Pb 2+ , to realize orientational growth of single-crystalline CsPbBr 3 microwires. Strong electrostatic interactions localized at air-liquid interface not only support preferential nucleation for single crystallinity, but also select the crystal facet with the highest Pb 2+ areal density for pure crystallographic orientation. Due to the epitaxy at air-liquid interface, we realize direct growth of oriented single-crystalline microwires onto different substrates without the processes of lift-off and transfer. Photonic lasing emission, waveguide coupling and on-chip propagation of coherent light are demonstrated based on these single-crystalline microwires. Our findings open an avenue for on-chip integration of single-crystalline materials. This article is protected by copyright. All rights reserved.