The explosively developed era of big-data compels the increasing demand of nonvolatile memory with high efficiency and excellent storage properties. Herein, we fabricated a high-speed photoelectric multilevel memory device for neuromorphic computing. The novel two-dimensional (2D) MoSSe with a unique Janus structure was employed as the channel, and the stack of Al₂O₃/black phosphorus quantum dots (BPQDs)/Al₂O₃ was adopted as the dielectric. The storage performance of the resulting memory could be verified by the endurance and retention tests, in which the device could remain stable states of programming and erasing even after 1, 000 cycles and 1, 000 s. The multibit storage could be realized through both different voltage amplitudes and pulse numbers, which could achieve 6 bits (64 distinguishable levels) under pulse width of 50 ns. Furthermore, our memory device also could realize the simulations of synapses in human brain with optical and electric modulations synergistically, such as excitatory post-synaptic current (EPSC), long-term potentiation/depression (LTP/LTD), and spike-timing-dependent plasticity (STDP). Neuromorphic computing was successfully achieved through a high recognition of handwritten digits up to 92.5% after 10³ epochs. This research is a promising avenue for the future development of efficient memory and artificial neural network systems.

Atomic layer deposition (ALD) can be used for wafer-scale synthesis of 2D materials. In this paper, a novel, reliable, secure, low-cost, and high-efficiency process for the fabrication of MoS₂ is introduced and investigated. The resulting 2D materials show high carrier-mobility as well as excellent electrical uniformity. Using molybdenum pentachloride (MoCl₅) and hexamethyldisilathiane (HMDST) as ALD precursors, thickness-controlled MoS₂ films are uniformly deposited on a 50 mm sapphire and a 100 mm silica substrate. This is done with a high growth-rate (up to 0.90 Å/cycle). Large-scale top-gated FET arrays are fabricated using the films, with a room-temperature mobility of 0.56 cm²/(V·s) and a high on/off current ratio of 10⁶. Excellent electrical uniformity is observed in the whole sapphire wafer. Additionally, logical circuits, including inverters, NAND, AND, NOR, and OR gates, are realized successfully with a high-k HfO₂ dielectric layer. Our inverters exhibit a fast response frequency of 50 Hz and a DC-voltage gain of 4 at V_DD = 4 V. These results indicate that the new method has the potential to synthesize high quality MoS₂ films on a large-scale, with hypo-toxicity and enhanced efficiency, which can facilitate a broader range of applications in the future.