[10p-S5-1~14] 3.12 Semiconductor optical devices

4:45 PM - 5:00 PM JST(7:45 AM - 8:00 AM UTC)English Presentation

[10p-S5-13] Tuning Band Alignment of Heterostructure CsPbCl₃/PbF₂/CsSnCl₃ via van der Waals Gap Engineering: A First-Principles Study

〇(D)SOULAYMANE AITBEN HSSEIN¹, KOHJI NAKAMURA¹ (1.Mie Univ.)

Keywords:

Perovskite Materials,Interface

In high-performance optoelectronic devices, semiconductor physics at heterostructure interfaces fundamentally governs device efficiency and carrier dynamics [1]. Unlike conventional interfaces, van der Waals (vdW) heterostructures tune electronic properties via weak interlayer couplings without lattice-mismatch constraints. In this work, we utilize first-principles calculations via the full-potential linearized augmented plane wave (FLAPW) method [2] under the generalized gradient approximation (GGA) to systematically investigate a novel CsPbCl₃/PbF₂/CsSnCl₃ vdW heterostructure. The model features an upper CsSnCl₃ slab and a lower CsPbCl₃ slab functionalized with a chemically bonded PbF₂ layer, separated by a variable physical vdW gap. At a vdW distance of 6.87Å, the heterostructure exhibits a type-I band alignment with a 1.69 eV bandgap dominated by the CsSnCl₃ layer. Reducing this distance to 4.32Å preserves the alignment and total bandgap, but the functionalized CsPbCl₃ layer's bandgap decreases from 2.4 eV to 2.2 eV, shifting its conduction band minimum closer to that of CsSnCl₃. Electrostatic potential calculations reveal that the PbF₂ layer possesses a deeper potential than CsSnCl₃, inducing a built-in electric field with a potential drop of 6.23 eV. Charge density difference analysis indicates electron accumulation in the CsPbCl₃ region and depletion in CsSnCl₃, driving the formation of an interfacial dipole. These findings offer promising insights for advancing nanoelectronic and optoelectronic device design.
[1] D. A. Tatarinov et al., Adv. Sci. 12, e05971 (2025).
[2] K. Nakamura, et al., Phys. Rev. B 67, 014420 (2003)