Grain boundaries in two-dimensional(2D)semiconductors generally induce distorted band alignment and interfacial charge,which impair their electronic properties for device applications.Here,we report the improvement of...Grain boundaries in two-dimensional(2D)semiconductors generally induce distorted band alignment and interfacial charge,which impair their electronic properties for device applications.Here,we report the improvement of band alignment at the grain boundaries of PtSe_(2),a 2D semiconductor,with selective adsorption of a presentative organic acceptor,tetracyanoquinodimethane(TCNQ).TCNQ molecules show selective adsorption at the PtSe_(2)grain boundary with strong interfacial charge.The adsorption of TCNQ distinctly improves the band alignment at the PtSe_(2)grain boundaries.With the charge transfer between the grain boundary and TCNQ,the local charge is inhibited,and the band bending at the grain boundary is suppressed,as revealed by the scanning tunneling microscopy and spectroscopy(STM/S)results.Our finding provides an effective method for the advancement of the band alignment at the grain boundary by functional molecules,improving the electronic properties of 2D semiconductors for their future applications.展开更多
With the unique properties,layered transition metal dichalcogenide(TMD)and its heterostructures exhibit great potential for applications in electronics.The electrical performance,e.g.,contact barrier and resistance to...With the unique properties,layered transition metal dichalcogenide(TMD)and its heterostructures exhibit great potential for applications in electronics.The electrical performance,e.g.,contact barrier and resistance to electrodes,of TMD heterostructure devices can be significantly tailored by employing the functional layers,called interlayer engineering.At the interface between different TMD layers,the dangling-bond states normally exist and act as traps against charge carrier flow.In this study,we propose a technique to suppress such carrier trap that uses enhanced interlayer hybridization to saturate dangling-bond states,as demonstrated in a strongly interlayer-coupled monolayer-bilayer PtSe2 heterostructure.The hybridization between the unsaturated states and the interlayer electronic states of PtSe2 significantly reduces the depth of carrier traps at the interface,as corroborated by our scanning tunnelling spectroscopic measurements and density functional theory calculations.The suppressed interfacial trap demonstrates that interlayer saturation may offer an efficient way to relay the charge flow at the interface of TMD heterostructures.Thus,this technique provides an effective way for optimizing the interface contact,the crucial issue exists in two-dimensional electronic community.展开更多
基金the National Key Research and Development Program of China(Nos.2021YFA1400100,2020YFA0308800,and 2019YFA0308000)the National Natural Science Foundation of China(Nos.92163206 and 62171035)+2 种基金the Beijing Nova Program from Beijing Municipal Science&Technology Commission(No.Z211100002121072)the Beijing Natural Science Foundation(Nos.Z190006 and 4192054)Calculations were performed at the Physics Lab of High-Performance Computing of Renmin University of China,and Beijing Super Cloud Computing Center.
文摘Grain boundaries in two-dimensional(2D)semiconductors generally induce distorted band alignment and interfacial charge,which impair their electronic properties for device applications.Here,we report the improvement of band alignment at the grain boundaries of PtSe_(2),a 2D semiconductor,with selective adsorption of a presentative organic acceptor,tetracyanoquinodimethane(TCNQ).TCNQ molecules show selective adsorption at the PtSe_(2)grain boundary with strong interfacial charge.The adsorption of TCNQ distinctly improves the band alignment at the PtSe_(2)grain boundaries.With the charge transfer between the grain boundary and TCNQ,the local charge is inhibited,and the band bending at the grain boundary is suppressed,as revealed by the scanning tunneling microscopy and spectroscopy(STM/S)results.Our finding provides an effective method for the advancement of the band alignment at the grain boundary by functional molecules,improving the electronic properties of 2D semiconductors for their future applications.
基金We acknowledged the financial support from the Beijing Natural Science Foundation(Nos.Z190006 and 4192054)the National Natural Science Foundation of China(Nos.61725107,11622437,61674171,11974422,61761166009,and 61888102)+3 种基金the National Key Research&Development Projects of China(Nos.2016YFA0202301,2019YFA0308000,and 2018YFE0202700)the Fundamental Research Funds for the Central Universities,China and the Research Funds of Renmin University of China(Nos.16XNLQ01 and 19XNQ025)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB30000000 and XDB28000000)Calculations were performed at the Physics Lab of High-Performance Computing of Renmin University of China and Shanghai Supercomputer Center.
文摘With the unique properties,layered transition metal dichalcogenide(TMD)and its heterostructures exhibit great potential for applications in electronics.The electrical performance,e.g.,contact barrier and resistance to electrodes,of TMD heterostructure devices can be significantly tailored by employing the functional layers,called interlayer engineering.At the interface between different TMD layers,the dangling-bond states normally exist and act as traps against charge carrier flow.In this study,we propose a technique to suppress such carrier trap that uses enhanced interlayer hybridization to saturate dangling-bond states,as demonstrated in a strongly interlayer-coupled monolayer-bilayer PtSe2 heterostructure.The hybridization between the unsaturated states and the interlayer electronic states of PtSe2 significantly reduces the depth of carrier traps at the interface,as corroborated by our scanning tunnelling spectroscopic measurements and density functional theory calculations.The suppressed interfacial trap demonstrates that interlayer saturation may offer an efficient way to relay the charge flow at the interface of TMD heterostructures.Thus,this technique provides an effective way for optimizing the interface contact,the crucial issue exists in two-dimensional electronic community.