Study of electronic structure regulation of α-In2Se3/PtX2(X=S,Se,Te)heterojunction
Two-dimensional(2D)van der Waals(vdW)heterojunctions hold significant promise for high-performance electronics in the post-Moore era,owing to their unique properties including dangling bond-free interfaces and minimal stress mismatch.However,the static nature of the atomic structures in existing 2D vdW heterojunctions poses a challenge for dynamically tuning their physical properties.To address this limitation,it is proposed to construct vdW heterojunctions comprising the 2D ferroelectric material α-In2Se3 and PtX2(X=S,Se,Te).The structure of α-In2Se3 can then be modulated using an electric field,enabling dynamic adjustment of the atomic and electronic structures of α-In2 Se3/PtX2.Based on the first-principles calculations,the band gaps of the heterojunctions are shown to depend on the polarization direction of α-In2Se3.Specifically,the band gaps of α-In2Se3/PtS2,α-In2Se3/PtSe2 and α-In2Se3/PtTe2 are found to be 1.25/1.66 eV,0.74/1.34 eV and 0.34/0.77 eV,respectively.Moreover,the polarization flip in α-In2Se3 facilitates a notable shift in heterojunction band alignment:α-In2 Se3/PtS2 transitions from type-Ⅰ to type-Ⅱ band alignment;α-In2 Se3/PtSe2 exhibits modifications in the relative positions of its energy bands though maintaining type-Ⅱ band alignment;and α-In2 Se3/PtTe2 transitions from type-Ⅱ to type-Ⅰ band alignment.The technical pathway for modulating the electronic states of 2D vdW heterojunctions via the polarization flip of α-In2Se3 offers a potential technological foundation for the development of future smart electronic devices.
ferroelectricitytwo-dimensional materialsvan der Waals heterojunctionelectronic structure
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