碳纳米管薄膜晶体管中的接触电阻效应

利用不同功函数的金属作为接触电极,研究了网络状碳纳米管薄膜晶体管(CNT-TFT)的接触电阻效应。研究表明金属Pd与碳纳米管薄膜形成良好的欧姆接触, Au则形成近欧姆接触,这两种接触的器件的开态电流和迁移率较高。Ti和Al都与碳纳米管薄膜形成肖特基接触,且Al接触比Ti接触的势垒更高,接触电阻也更大,相应器件的开态电流和迁移率都较低。该结果表明对于CNT-TFT仍然可以通过接触来调控器件的性能,这对CNT-TFT的实用化进程具有重要的促进作用。     

Finite superconducting square wire-network based on two-dimensional crystalline Mo2C

Superconducting wire-networks are paradigms to study Cooper pairing issues, vortex dynamics and arrangements. Recently, emergent low-dimensional crystalline superconductors were reported in the minimal-disorder limit, providing novel platforms to reveal vortices-related physics. Study on superconducting loops with high-crystallinity is thus currently demanded. Here, we report fabrication and transport measurement of finite square-network based on two-dimensional crystalline superconductor Mo₂C. We observe oscillations in the resistance as a function of the magnetic flux through the loops. Resistance dips at both matching field and fractional fillings are revealed. Temperature and current evolutions are carried out in magnetoresistance to study vortex dynamics. The amplitude of oscillation is enhanced due to the interaction between thermally activated vortices and the currents induced in the loops. The driving current reduces the effective activation energy for vortex, giving rise to stronger vortex interaction. Moreover, by the thermally activated vortex creep model, we derive the effective potential barrier for vortex dissipation, which shows well-defined correspondence with structures in magnetoresistance. Our work shows that low-dimensional crystalline superconducting network based on Mo₂C possesses pronounced potential in studying the modulation of vortex arrangements and dynamics, paving the way for further investigations on crystalline superconducting network with various configurations.     

多壁碳纳米管互连的单壁碳纳米管晶体管的频率特性

用多壁碳纳米管(MWCNTs)作为互连线制备出了单壁碳纳米管场效应晶体管(SWCNT FETs), 对比研究了用多壁碳纳米管作为互连线和用金属作为互连线的两种情况. 结果表明, 二者的直流(DC)性能基本一致, 而用多壁碳纳米管作为互连线的交流(AC)性能略优于用金属作为互连的情况. 交流测量表明, 至少在20 MHz的频率下, 多壁碳纳米管互连的单壁碳纳米管晶体管仍有很好的响应速率, 器件能够正常工作.     

碳纳米管室温单电子器件的构建和特性测量

利用传统微加工与纳米组装技术构建出了金属颗粒调制的复合碳纳米管场效应及单电子器件，电子输运性能测量结果表明这类复合碳纳米器件具有一些不同于一般碳纳米单电子器件的独特性能，特别是可在室温下实现单电子特性。