Two-dimensional van der Waals materials based nonvolatile memory field-effect transistors (Conference Presentation)

Two-dimensional van der Waals (2D vdWs) materials are a class of new materials that can provide important resources for future electronics and materials sciences due to their unique physical properties. Molybdenum disulfide (MoS2) is one of the most promising n-type TMD semiconductors. Several research groups reported on MoS2 nanosheet based transistors that exhibit satisfactory carrier mobility values with high on/off current ratios. On the other hand, a newly discovered 2D vdWs material, called black phosphorous (BP), has generated considerable scientific and technological interest in the research community. 2D BP also has considerable potential for electronic and optoelectronic applications. This is evidenced by recent research on FETs, diodes, and photodetectors involving few-layered BP flakes. Here, we report on a high performance MoS2 and BP nanosheet based nonvolatile memory transistors with a poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) ferroelectric top gate insulator. The MoS2 ferroelectric field-effect transistor (FeFET) shows a highest linear electron mobility value of 175 cm2/Vs with a high on/off current ratio more than 107, and a very clear memory window over 15 V. The program and erase dynamics and static retention properties are also well demonstrated. Our BP ferroelectric FETs (FeFETs) also exhibit a clear memory window of 15 V and a highest linear mobility value of 1159 cm2V-1s-1 with a 103 on/off current ratio at room temperature in ambient air. In order to explore advanced memory applications beyond unit memory devices, we implement two kinds of memory inverter circuits: a resistive-load inverter circuit and a CMOS inverter circuit combined with n-type MoS2.