Dynamic Control of Band Alignment and Built-In Potential in High Performance Self-Powered InSe/SnS2 Van der Waals Photodetectors via Gas Molecular Physisorption
Cao Z. Abid M. Ó Coileáin C. An F. Chang C.-R. Wu Y.-R. Wu H.-C.
March 2026John Wiley and Sons Inc
Small Science
2026#6Issue 3
Molecular physisorption provides a versatile strategy to dynamically tailor the optoelectronic properties of van der Waals (vdW) heterostructures, enabling extended carrier lifetimes, broadened spectral response, and erasable memory effects in self-powered photodetectors. Here, we report how NO2 physisorption precisely modulates band alignment and built-in potentials in self-powered InSe/SnS2 heterojunction photodetectors. Using electrostatic gating, we identify three distinct regimes: (I) a robust p–n configuration (Vg ≤ –50 V), where adsorption induces a collective electron-withdrawing effect, enabling efficient p-i-n-like behavior with near-ideal charge separation; (II) an intermediate p–n regime (–50 V < Vg < –30 V), where competing electron withdrawal and recombination effects allow dynamic tuning the electronic structure and optoelectronic properties, and (III) an illumination-sensitive n–n+ mode (Vg ≥ –30 V), where NO2 molecules act as recombination centers, suppressing the built-in potential. This dual control via gating and molecular adsorption provides unprecedented manipulation of charge separation and transport, opening avenues for next-generation multifunctional optoelectronic devices.
band alignment , built-in potential , gas physisorption , InSe/SnS2 , self-powered photodetectors , van der waals heterojunction
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School of Physics, Beijing Institute of Technology, Beijing, China
EduAI dynamics, Astana, Kazakhstan
Department of Electrical Power Systems and Information Technology, Institute of Physics, University of the Bundeswehr Munich, Neubiberg, Germany
State Key Laboratory of Explosion Science and Safety, Beijing Institute of Technology, Beijing, China
Department of Physics, National Taiwan University, Taipei, Taiwan
Quantum Information Center, Chung Yuan Christian University, Taoyuan, Taiwan
Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
School of Physics
EduAI dynamics
Department of Electrical Power Systems and Information Technology
State Key Laboratory of Explosion Science and Safety
Department of Physics
Quantum Information Center
Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering
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