Polarization-dimension competition in centrosymmetric flexoelectronic transistors

Abstract

Flexoelectricity that polarizes crystal by strain gradient offers an emerging interface engineering for the development of all-material functional electronics. As a new device paradigm, flexoelectronics enables the enhancement of electromechanical coupling in centrosymmetric semiconductors, however, the underline modulation is still required further understood. Here, we present a theoretical study of charge transport in silicon-based flexoelectronic transistors subjected to nanoscale tip loading. The results suggest that the mechanical load governs the current through two coupled mechanisms: strain-gradient-induced flexoelectric polarization that tunes the interfacial barrier, and load-dependent contact enlargement that introduces an additional, often non-negligible, dimensional contribution to conduction. These two effects act in opposite roles for p- and n-type devices, which causes a unique polarization–dimension competition for transport modulation. Moreover, increasing the tip radius weakens the polarization-driven modulation while strengthening the dimensional effect, providing a straightforward strategy to boost strain sensitivity via geometry design. These findings identify a distinctive regulation paradigm in flexoelectronic transistors and provide practical guidance for device optimization through geometry engineering.