Studies On Integrated Molecular Circuits With Multichannel Structure

Integrated circuit is a kind of microelectronic device that connects the components required in a certain way to form a preset function.Nowadays widely used silicon-based integrated circuits have reached the lowest limit of physical size of silicon-based semiconductor materials in pursuit of high device density and small device size.Molecular electronics is considered as a challenging and prospective science to solve the dimension problem of integrated circuit devices.Molecular electronics demonstrates the feasibility of constructing circuits from individual molecules at micro and nano scales.If molecular devices are to supplement or even replace traditional semiconductor devices,they should also have electronic components that can match the function of traditional integrated circuits.At present,although there have been preliminary theoretical and experimental studies on molecular circuits,it has not been attempted to further form molecular circuits into “higher-level” integrated molecular circuits.The most basic structural forms and theoretical requirements in this field need to be excavated and explored by researchers.Therefore,this work is focused on attempts to build integrated molecular circuits by connecting molecular circuits with series structure and molecular circuits with parallel structure.According to the performance of integrated molecular circuits under this structural model,we summarize the structural design principles and conductivity characteristics of integrated molecular circuits,so as to provide theoretical basis and design concept for the development of integrated molecular circuits.To this end,a series of molecules with multi-channel structures are used to construct integrated molecular circuits.In view of the excellent conjugation and electron transport characteristics of oligopolyacetylene(OPE)derivatives,they are judiciously utilized as a framework to design the multi-channel structure in this work.Because there is a more reasonable theoretical basis for the series molecular circuit,this work is focused on using the multi-channel molecular structure to construct the parallel circuit in the integrated molecular circuit and exploring the transmission channel and conductivity characteristics of electrons in the integrated molecular circuit.The results of single molecule conductance measured by scanning tunneling microscope molecular junction splitting junction(STM-BJ)technology show that this series of multichannel molecules have simple structures and integrated molecular circuits with accurately calculated conductance.The conductance can be deduced according to the structural changes so that some structural and performance issues of the integrated molecular circuit have been addressed.The main research results of integrated molecular circuits in this work are shown as follows.(1)Integrated molecular circuits with multichannel structures based on phenyl m-para connection.Using 4-bromoanisole sulfide,p-bromobenzyl bromide and3,4-dimethylbromobenzene as synthetic materials,two molecules with integrated molecular circuit structures and other relevant reference molecules based on oligopolyacetylene(OPE)were designed and synthesized.The single-molecule conductance of this series of molecules was systematically characterized by STM-BJ technology.It is demonstrated electrons transport is conducted through meta and para positions of benzene framework in different ratios,and the proportion of electrons transported through the channels at meta-position are four times that at the para-position.(2)Integrated molecular circuit of multichannel structures based on ortho-and meta-position linkages at benzene frameworks.Using 4-Bromoanisole sulfide,m-bromobenzyl bromide and 3-bromo-o-xylene as synthetic materials,an OPE based molecule with integrated molecular circuit structure and related reference molecules were designed and synthesized.The single molecule conductance of these molecules was fully characterized by STM-BJ technology.By comparing and analyzing the conductance of relevant reference molecules,it is concluded that the probability of electron transport through ortho-position channel is basically the same as that through meta-position channel.