Dynamic Control of Band Alignment and Built‐In Potential in High Performance Self‐Powered InSe/SnS 2 Van der Waals Photodetectors via Gas Molecular Physisorption
Journal
Small Science
Series/Report No.
Small Science
Journal Volume
6
Journal Issue
3
Start Page
e202500616
ISSN
2688-4046
2688-4046
Date Issued
2026-03-06
Author(s)
Abstract
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.
Subjects
band alignment
built-in potential
gas physisorption
InSe/SnS2
self-powered photodetectors
van der waals heterojunction
Publisher
Wiley
Type
journal article