Effect of the contact distance on transport properties of an organic molecular device  

作　　者：ZHANG ZhenHua YANG ZhongQin YUAN JianHui QIU Ming 

机构地区：[1]School of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410076, China [2]Surface Physics Laboratory (National Key Laboratory), Fudan University, Shanghai 200433, China

出　　处：《Chinese Science Bulletin》2007年第21期3016-3019,共4页

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 607710598 & 10674027);the Provincial Natural Science Foundation of Hunan (Grant No. 03JJY3013);the Doctoral Program Foundation of Ministry of Education of China (Grant No. 20030532008);the Foundation of Excellent Ph.D.Thesis of Hunan Province (Grant No. 200526);the Scientific Research Fund of Hunan Provincial Education Department (Grant No. 05B023)

摘　　要：Using a spatially symmetric phenyldithiolate molecule sandwiched between two gold electrodes as model system and through shifting one electrode from symmetric contact site to form asymmetric contact, we investigated the properties of electronic transport in such a device by the first-principles. It was found that the I(G )-V characteristics of a device show significant asymmetry and the magnitudes of current and conductance depend remarkably on the variation of molecule-metal distance at one of the two contacts. Namely, an asymmetric contact would lead to the weak rectifying effects on the cur- rent-voltage characteristics of a molecular device. The analysis shows that the HOMO is responsible for the resonant tunneling and its shift due to the charging of the device while the bias voltage is the intrinsic origin of asymmetric I(G)-V characteristics.Using a spatially symmetric phenyldithiolate molecule sandwiched between two gold electrodes as model system and through shifting one electrode from symmetric contact site to form asymmetric contact, we investigated the properties of electronic transport in such a device by the first-principles. It was found that the/（G ）-V characteristics of a device show significant asymmetry and the magnitudes of current and conductance depend remarkably on the variation of molecule-metal distance at one of the two contacts. Namely, an asymmetric contact would lead to the weak rectifying effects on the current-voltage characteristics of a molecular device. The analysis shows that the HOMO is responsible for the resonant tunneling and its shift due to the charging of the device while the bias voltage is the intrinsic origin of asymmetric/（G）- Vcharacteristics.

关 键 词：分子器件 不对称触点 电流 电压 

分 类 号：TM0[电气工程—电工理论与新技术]