Research On The Resistance Switching Performance Of Two-dimensional Material WSe_2-xO_y Memristor

The last few years have witnessed the rapid evolvement of artificial intelligence(AI),especially software AI thanks to the advances in the development of algorithm.hardware AI system based on in-memory computing architecture can solve probabilistic and unstructured problems with low power dissipation resembling biological neural networks.Recently,the memristive device has attracted intensive attention as a promising candidate in hardware neuromorphic computing due to its prominent advantages,including simple sandwich structure and rich switching dynamics resembling biological synapses and neurons.And,extensive efforts have been devoted to developing memristive synapses and neurons as building blocks to build high power-efficient neuromorphic computing system.Till now,the most reported mainstream memristive materials are thin films of transition metal oxides.It is worth noting that these thin films are intrinsic rigid,severely limiting their applications in flexible devices.Fortunately,two-dimensional(2D)materials with natural flexibility have attracted intensive attention recently.And it is found that these2D materials have prospective potential for applications in the next generation of electronic products with flexibility,transparency,lightness and portability.Specially,flexible memristive devices demonstrated based on 2D materials have recently been in the spotlight in the field of memristors.Here,2D WSe₂ was chosen as memristive devices and the main research contents are as follows:First,Pd/WSe₂/Pd memristive devices were prepared through magnetron sputtering,mechanical exfoliation and PDMS transfer technology.To improve the memristive performance of the Pd/WSe₂/Pd devices,oxygen plasma treatment was employed to modulate the microstructure of WSe₂.And it is found that some local region of amorphous WO_3-x formed after oxygen plasma treatment.Thus,the WSe₂suffered oxygen plasma treatment is labeled as WSe_{2-x Oy}.Furthermore,the dependence of testing atmosphere on the resistive switching behavior of the device was investigated.It is found stable resistive switching can be achieved only in oxygen rich atmospheres,indicating that the resistive switching originated from the variation of the interface barrier due to oxygen vacancies migration in the interface of Pt/WSe2-x Oy.Then,graphene(Gr)was utilized as the electrodes instead of metal Pd,and full2D Gr/WSe_2-xO_y/Gr memristive devices are prepared.The influence of plasma treatment parameters and testing atmospheres was systemically studied to disclose the resistive switching mechanism of the Gr/WSe_2-xO_y/Gr memristive devices.Experimental results indicate that the resistive switching is attributed to the migration of oxygen vacancies at the interface of Gr/WSe_2-xO_y.More importantly,versatile synaptic functions,including STP,LTP and the transition from STP to LTP,were vividly mimicked based on the prepared full 2D Gr/WSe_2-xO_y/Gr device.Finally,a flexible 2D memristive device of Gr/WSe_2-xO_y/Gr was prepared on PI substrate,and the resistive switching performance of the flexible device was investigated.It is found these flexible memristive devices exhibit stable switching behavior under bending,indicating these full 2D memristive device have prospective potential for the application of next-generation devices with features of wearable,high-flexibility and transparent.