Compared to traditional bulk materials, two-dimensional transition metal dichalcogenides (2D TMDCs) hold the potential in low power logic, photoelectric, and nonvolatile memory devices due to a tunable band structure, pure heterojunction interface, and photodetection for a wide spectral range. ReS 2 is chosen as the channel material in our work because it possesses excellent photoresponsivity. In addition, a BN dielectric is inserted between SiO 2 and ReS 2 as a gate dielectric. The pure heterojunction interface at BN/ReS 2 enhances the electric characteristics, including negligible hysteresis window and higher mobility. The photoelectric measurement results show that ReS 2 devices with or without the BN dielectric have an outstanding photoresponsivity of up to ∼10 6 A/W and a specific detectivity of up to ∼10 13 Jones as well as a fast photoresponse time of less than 100 ms under an extremely low optical power density of 0.47 μW/cm 2 , which fully proves that ReS 2 has the ability to detect very weak light. Also, the contact resistance and Schottky barrier height are also extracted with variable temperature measurements for the ReS 2 device. The higher contact resistance and unsymmetric output currents illustrate that the mirror force is the main factor leading to the reduction of the Schottky barrier height. Finally, the influences of the ReS 2 channel thickness on mobility and photoresponsivity are also studied by the device-to-device variability. The work in this paper further demonstrates that nanosheet-based ReS 2 can be regarded as an excellent candidate for application into the field of light-sensitive sensors under the condition of the CMOS-compatible process.

With the advent of post-Moore era, the development of memory devices based on bulk materials gradually entered the bottleneck period. Two-dimensional (2D) materials have received much attention due to their excellent optoelectronic and mechanical properties. Also, floating-gate devices based on 2D van der Waals heterostructures have drawn widespread attention in virtue of their great potential for nonvolatile memory. In this paper, a floating-gate device based on a MoS 2 /BN/graphene heterostructure was fabricated and its electrical storage performance and synaptic function were investigated. Finally, the device obtains a switching ratio of close to ∼10 5 , a large storage window of 107.8 V under a sweeping range of ±60 V, good endurance after 1000 cycles, and charge retention capability above 1500 s. In addition, the device can be used as an artificial synapse to simulate a basic synaptic function and achieve a more linear and symmetrical longterm potentiation and long-term depression profiles. At the same time, the constructed convolutional neural network using this device reaches a high recognition accuracy of 95.5% for handwritten numerals after 1000 times training. These results demonstrate the great potential of 2D material floating-gate devices for nonvolatile memory and neuromorphic computing, which pave the way for the development of next-generation memory devices.