WSe2 2D p-type semiconductor-based electronic devices for information technology:Design,preparation,and applications

The pioneering exfoliation of monolayer tungsten diselenide has greatly inspired researchers toward semiconducting applications.WSe2 belongs to a family of transition-metal dichalcogenides.Similar to graphene,WSe2 and analogous dichalcogenides have layered structures with weak van der Waals interactions between two adjacent layers.First,the readers are presented with the fundamentals of WSe2,such as types,morphologies,and properties.Here,we report the characterization principles and practices such as microscopy,spectroscopy,and diffraction.Second,the methods for obtaining high-quality WSe2,such as exfoliation,hydrothermal and chemical vapor deposition,are briefly listed.With advantages of light weight,flexibility,and high quantum efficiency,2D materials may have a niche in optoelectronics as building blocks in p-n junctions.Therefore,we introduce a state-of-the-art demonstration of heterostructure devices employing the p-type WSe2 semiconductor.The device architectures include field-effect transistors,photodetectors,gas sensors,and photovoltaic solar cells.Due to its unique electronic,optical,and energy band properties,WSe2 has been increasingly investigated due to the conductivity of the p-type charge carrier upon palladium contact.Eventually,the dynamic research on WSe2 and van der Waals heterostructures is summarized to arouse the passion of the 2D research community.

Ultrasensitive and stable all graphene field-effect transistor-based Hg^(2+)sensor constructed by using different covalently bonded RGO films assembled by different conjugate linking molecules

As"molecular bridge,"coupling agents can not only realize the covalent connection of composites,but also affect their properties,thus affecting the properties of devices based on them.Herein,leveraging differences in charge conduction properties of the(3-aminopropyl)trimethoxysilane and 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphine caused by conjugacy structural differences,two kinds of layerby-layer assembled smart carbon materials with different electrical properties are obtained at the same reduction temperature.The two graphene ultrathin films are then“planted”on Si/SiO2 substrates,respectively,as semiconductor layer and source/drain electrodes to fabricate an ultra-stable all-graphene field effect transistor(AG-FET).Enabled by the covalent functionalized configuration and the functionally diverse of coupling agents,the AG-FET obtained by this simple method won the high electrical characteristics,the hole,electron mobility,and the shelflife could reach 3.79 cm2/(V·s),3.78 cm2/(V·s),and 18months,respectively.In addition,good material stability and excellent device structure endow the device exceptional stability,electrical stability,and solvent resistance,improving its application prospect in solution phase sensing/detection.Such characteristics could be used to sense,transduce,and respond to external stimuli,especially in solution phase to monitor the important analytes,such as Hg^(2+)in a flowing sewage environment.We believe that such easy-to-manufacture AG-FETs with ultrahigh performance and ultrahigh stability could also show great application prospects in other significant fields.

A multiobjective discrete combination optimization method for dynamics design of engineering structures

This paper presents a new multiobjective discrete optimization method for the engineering design of dynamic problems.A discrete combinatorial optimization problem is solved using a particle swarm optimization algorithm coupled with a stair‐form interpolation model.To address multiobjective optimization issues,a weighted average approach is implemented to convert the multiobjective optimization problem into an equivalent single‐objective optimization problem.Design con-straints are taken into consideration by using the penalty function strategy.The proposed method is first verified with a 10‐bar truss structure design problem,where the cross‐sectional area of each bar is optimized to minimize both volume and node displacement.Second,the dynamic issue for hybrid composite laminates is investigated by maximizing the fundamental frequency and minimizing the cost.The results reveal that the optimized results generated by the proposed method agree well with those from other approaches.