Ambipolar MoS2 Field Effect Transistors with Negative Photoconductivity and High Responsivity Using an Ultrathin Epitaxial Ferroelectric Gate

Ferroelectric field effect transistors (FeFETs), characterized by their low power consumption and polarization effect, can be employed in photodetectors based on 2D materials. In this paper, a MoS2 phototransistor with epitaxial ferroelectric (Hf0.5Zr0.5)O-2 (HZO) is reported as a gate dielectric layer. Gate-dielectric-polarization-dependent ambipolar behavior is observed in the FET, and relatively low power consumption and hysteresis-free loop are achieved in the FeFET. The anomalous negative photoconductivity (NPC) is observed as well. Possible reasons for such phenomenon are clarified including the photogating effect originating from the interface traps and the polarization-dependent electric-field control through ferroelectric gating. The high responsivity of -8.44 x 10(3) A W-1 in the negative photoconductivity as well as the response time of 500 ms are reported. The demonstrated Molybdenum disulfide (MoS2) FeFET photodetectors show great potential in the on-chip complementary metal-oxide semiconductor (CMOS)-compatible circuits for multifunctional devices.