Memristors have attracted tremendous interest in the fields of high-density memory and neuromorphic computing.However,despite the tremendous efforts that have been devoted over recent years,high operating voltage,poor...Memristors have attracted tremendous interest in the fields of high-density memory and neuromorphic computing.However,despite the tremendous efforts that have been devoted over recent years,high operating voltage,poor stability,and large device variability remain key limitations for its practical application and can be partially attributed to the un-optimized interfaces between electrodes and the channel material.We demonstrate,for the first time,a van der Waals(vdW)memristor by physically sandwiching pre-fabricated metal electrodes on both sides of the two-dimensional channel material.The atomically flat bottom electrode ensures intimate contact between the channel and electrode(hence low operation voltage),and the vdW integration of the top electrode avoids the damage induced by aggressive fabrication processes(e.g.sputtering,lithography)directly applied to the channel material,improving device stability.Together,we demonstrate memristor arrays with a high integration density of 10^(10)cm^(−2),high stability,and the lowest set/reset voltage of 0.12 V/0.04 V,which is a record low value for all 2D-based memristors,as far as we know.Furthermore,detailed characterizations are conducted to confirm that the improved memristor behavior is the result of optimized metal/channel interfaces.Our study not only demonstrates robust and low voltage memristor,but also provides a general electrode integration approach for other memristors,such as oxide based memristors,that have previously been limited by non-ideal contact integration,high operation voltage and poor device stability.展开更多
A boundary element method for simulating thermocapillary convection in a two-layer immiscible fluid system with flat and free interface has been developed.The divergence theorem is applied to the non-linear convective...A boundary element method for simulating thermocapillary convection in a two-layer immiscible fluid system with flat and free interface has been developed.The divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty function.Consequently,velocity gradients are eliminated and the complete formulation is written in terms of velocity.This avoids the difficulty of convective discretizations and provides considerable reductions in storage and computational requirements while improving accuracy.In this paper,we give the influence of different parameters(Marangoni number, Reynolds number)on thermocapillary convection in cavity with two-layer immiscible fluids.As shown by the numerical results,when the physical parameters between liquid encapsulant and melt are chosen appropriately, the detrimental flow in the bottom melt layer can be greatly suppressed.The influence of the free interface on thermocapillary convection is also shown.展开更多
基金The authors acknowledge the financial support of the National Natural Science Foundation of China(Nos.51991340,51991341,51802090,and 61874041)the Hunan Science Fund for Excellent Young Scholars(No.812019037).
文摘Memristors have attracted tremendous interest in the fields of high-density memory and neuromorphic computing.However,despite the tremendous efforts that have been devoted over recent years,high operating voltage,poor stability,and large device variability remain key limitations for its practical application and can be partially attributed to the un-optimized interfaces between electrodes and the channel material.We demonstrate,for the first time,a van der Waals(vdW)memristor by physically sandwiching pre-fabricated metal electrodes on both sides of the two-dimensional channel material.The atomically flat bottom electrode ensures intimate contact between the channel and electrode(hence low operation voltage),and the vdW integration of the top electrode avoids the damage induced by aggressive fabrication processes(e.g.sputtering,lithography)directly applied to the channel material,improving device stability.Together,we demonstrate memristor arrays with a high integration density of 10^(10)cm^(−2),high stability,and the lowest set/reset voltage of 0.12 V/0.04 V,which is a record low value for all 2D-based memristors,as far as we know.Furthermore,detailed characterizations are conducted to confirm that the improved memristor behavior is the result of optimized metal/channel interfaces.Our study not only demonstrates robust and low voltage memristor,but also provides a general electrode integration approach for other memristors,such as oxide based memristors,that have previously been limited by non-ideal contact integration,high operation voltage and poor device stability.
基金Project supported by the National Natural Science Foundation of China
文摘A boundary element method for simulating thermocapillary convection in a two-layer immiscible fluid system with flat and free interface has been developed.The divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty function.Consequently,velocity gradients are eliminated and the complete formulation is written in terms of velocity.This avoids the difficulty of convective discretizations and provides considerable reductions in storage and computational requirements while improving accuracy.In this paper,we give the influence of different parameters(Marangoni number, Reynolds number)on thermocapillary convection in cavity with two-layer immiscible fluids.As shown by the numerical results,when the physical parameters between liquid encapsulant and melt are chosen appropriately, the detrimental flow in the bottom melt layer can be greatly suppressed.The influence of the free interface on thermocapillary convection is also shown.
