Synthesis of large two-dimensional lead-free bismuth-silver double perovskite microplatelets and their application for field-effect transistors.

Two-dimensional phenylethylammonium (PEA, C8H9NH3) Bi-Ag double perovskite (PEA)4BiAgX8 (X = Br, I) microplatelets are synthesized for the first time via a facile self-assembly recrystallization method. Absorption spectra of microplatelets exhibit direct bandgaps and different halide compositions show distinct morphologies and bandgap tunability. Field-effect transistors based on a single (PEA)4BiAgBr8 microplatelet display a p-type semiconducting behavior.

Lattice-Mismatched PbTe/ZnTe Heterostructure with High-Speed Midinfrared Photoresponses.

In this work, a novel heterostructure consisting of different lattice structures with zincblende ZnTe and rock-salt PbTe is proposed. The PbTe/ZnTe heterostructures are grown by molecular beam epitaxy. Type-I band alignment at the PbTe/ZnTe heterointerface is revealed by X-ray photoelectron spectroscopy. The interface of the heterostructure exhibits exotic electrical properties. The novel heterostructure is then implemented to develop high-performance mid-infrared photodetectors which demonstrate pronounced responsivity, swift response speed, and high detectivity. The new photodetectors utilize the lateral photovoltaic effect which facilitates the understanding of the novel PbTe/ZnTe heterostructures.