▎ 摘　　要

The Graphene@PtSe2 heterostructure is an excellent long-wave infrared detection material. However, the expensive cost of PtSe2 prevents its widespread use in infrared detection. In this paper, Hf was used to partially replace Pt to form Graphene@(PtSe2)(n)(HfSe2)(4-n) (n = 1, 2, and 3) bidirectional heterostructures consisting of graphene and lateral PtSe2/HfSe2 composites based on first-principles calculations. Then, the new bidirectional heterostructures were compared with heterostructures formed by graphene with pure MSe2 (M = Pt, Hf). It was found that the band gaps of the bidirectional heterostructures were between those of Graphene@PtSe2 and Graphene@HfSe2. Among these heterostructures, the Graphene@(PtSe2)(3)(HfSe2)(1) bidirectional heterostructure has almost the same optical absorption properties in the infrared wavelength region of 1.33 similar to 40 mu m as the Graphene@PtSe2 heterostructure, and it improves the absorption in the near-infrared wavelength region of 0.75 similar to 1.33 mu m. Such a designment may bring the material costs down (since PtSe2 costs approximately five times more than HfSe2). This study on the designment of the bidirectional Graphene@(PtSe2)(3)(HfSe2)(1) heterostructure also illustrates a cost-effective design method for Pt-based IR detectors.