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.