Work

Light-induced giant random telegraph noise in CuScP2S6/MoS2 heterostructures and their use in noise resilience image inference

Year: 2026

Type: article

Abstract: Random telegraph noise (RTN) is usually regarded as a hallmark of nanoscale conduction channels, arising from individual trapping events in semiconductors and oxide dielectrics. Here we show that optical excitation can induce “giant” RTN in macroscopically large-area devices based on CuScP2S6/MoS2 heterostructures, revealing a mesoscopic regime in which a sparse set of photo-activated defects in an insulating thiophosphate controls the conductance of an extended channel. Under optical illumination, the device conductance exhibits stochastic two-level fluctuations whose amplitudes are nearly independent of illumination strength, whereas the characteristic trapping–detrapping time constants are strongly governed by the incident light intensity. This behavior implies that photons are absorbed in effectively small packets that modulate a sparse ensemble of active traps, giving rise to bimodal noise statistics and illumination-tunable switching kinetics. We further exploit this controllable stochasticity in a proof-of-concept optical encoder that converts image pixels into RTN-driven spike trains, enhancing the robustness of a spiking neural network (SNN) to noise-corrupted MNIST inputs. Our results identify CuScP2S6 as a model platform in which light-tunable RTN connects microscopic defect dynamics to macroscopic conductance fluctuations, opening opportunities to engineer noise itself as a functional degree of freedom in photonic and neuromorphic hardware.

Source: Nature Communications

DOI: 10.1038/s41467-026-71034-6