Pyroelectric Doping Reversal of MoS₂ p‐n Junctions on Ferroelectric Domain Walls Probed by Photoluminescence

Abstract The possibility of modulating the electronic doping in monolayer MoS₂ using the pyroelectric effect of periodically poled LiNbO₃ (LN) substrates is demonstrated. Spatially resolved photoluminescence reveals that pyroelectric charges induced by temperature changes tune the carrier density in MoS₂ without the need for external gating. The results show a variation of the order of 10¹³ cm⁻² in the electron density as the temperature decreases from 300 to 10 K, which is consistent with the change in the value of the spontaneous polarization (P_S) of the LN substrate. Furthermore, upon cooling, pyroelectric charges effectively reverse the doping of monolayer MoS₂ in the proximity of ferroelectric domain walls (DWs), converting p‐n junctions into n‐p junctions. These findings highlight the potential of pyroelectric substrates for tunable and configurable charge engineering in transition metal dichalcogenides and suggest their applicability to other combinations of 2D materials and ferroelectric substrates. They also open avenues for alternative device architectures in nanoelectronic or nanophotonic devices including switches, or sensors.