Two dimensional CuInP2S6/h-BN/MoTe2 van der Waals heterostructure phototransistors with double gate control†

Abstract

Ferroelectric materials have demonstrated significant potential in the manipulation of optoelectronic processes in emerging device architectures. However, research exploring the synergy between ferroelectric materials and two-dimensional semiconductor materials, as well as direct modulation of the interface band alignment of two-dimensional semiconductor materials in heterostructures, remains limited. Here, we report a ferroelectric photodetector composed of a CuInP₂S₆ gate, an h-BN dielectric layer, and a MoTe₂ channel. Due to the presence of directional ferroelectric spontaneous polarization charges under an applied electric field, the interface band structure is effectively modulated, greatly enhancing the generation, separation, and transport efficiency of photo-generated electron–hole pairs. Compared to non-ferroelectric back-gated modulation (Si), the photocurrent is boosted by an order of magnitude under top-gate modulation, while the dark current is effectively suppressed. The ferroelectric photodetector exhibits a high responsivity modulation of 6.07 A W⁻¹ and a high detection rate of 5.67 × 10¹¹ jones. Interestingly, clockwise hysteresis is observed under both single top-gate (V_TG) and silicon dioxide back-gate (V_BG) modulation, attributed to the charge dynamics at the interface and gate coupling effects. This work reveals the substantial potential of the detector for high-performance optical sensing through the modulation of the interface band structure of semiconductor junctions by two-dimensional ferroelectric materials.