石墨烯场效应晶体管研究进展

制备场效应晶体管的石墨烯主要分三种类型:大面积单层石墨烯、石墨烯纳米带和双层石墨烯片。文中介绍了这三类石墨烯场效应晶体管器件的研究进展和标志性成果,探讨了石墨烯对于场效应晶体管的影响。研究认为:与大面积单层石墨烯晶体管相比,由石墨烯纳米带制得的石墨烯场效应晶体管的开关比和电流密度等性能能够大幅度提升,可应用于逻辑电路;与大面积单层石墨烯和石墨烯纳米带相比,双层石墨烯晶体管具有更高的开关比,因此其实际应用的潜力最大。     

异质栅氧化层石墨烯隧穿场效应管构建反相器

本文研究了不同结构的石墨烯纳米条带(GNR)隧道场效应晶体管(TFET)应用于反相器的性能.主要是在HSPICE中构建逻辑电路,并且基于Verilog-A模型的查找表进行的,主要比较了高K氧化层石墨烯隧穿场效应管(HKTINV)和异质氧化层石墨烯隧穿场效应管构建反相器(HTINV)的性能.     

GNRFET双极特性及工作区域研究

石墨烯器件作为下一代纳米电子器件的有力竞争者受到广泛关注,但对其器件工作机理的研究尚不透彻。对石墨烯纳米带场效应晶体管(graphene nanoribbon field effect transistor,GNRFET)的双极特性进行了研究,分析了偏置电压对GNRFET转移特性和输出特性的影响,发现除已被关注到的栅电压外,源漏电压对GNRFET的双极特性亦有作用,并将两者综合考虑才能全面反映GNRFET的工作状态。在此基础上,进一步提出了工作区域的概念,将GNR-FET的工作区域划分为空穴导电区、电子导电区、转变区和截止区,为GNRFET器件的应用和电路设计提供指导。     

石墨烯场效应管的Verilog-A建模

在传统硅基器件日益趋近物理极限的背景下,石墨烯场效应管作为一种新型纳米器件受到了广泛关注。以漂移-扩散传输理论为基础,得到了石墨烯场效应管的漏电流解析表达式,并以此建立了适合电路设计的石墨烯场效应管Verilog-A模型。利用该模型对栅长为10μm、沟道宽度为5μm的石墨烯场效应管进行HSPICE仿真,仿真结果与实验所测数据相符。在此基础上,给出了基于石墨烯场效应管的共源放大电路、共漏放大电路和共栅放大电路三种基本电路组态的仿真结果,表明石墨烯场效应管应用于模拟及RF电路具有广阔的前景。     

纳米银线/还原石墨烯复合材料的制备与表征

用改进的Hummer法制备了氧化石墨烯(GD),并制备 了表面用聚乙烯吡咯烷酮修饰的纳米银线(AgNWs), 通过原位还原法将二者复合成一种新型的水溶性AgNWs/还原石墨烯(RGD)材料,克服了石 墨烯材料不易分散 的缺点。用X射线衍射(XRD)、紫外-可见分光(UV-vis)光度计、扫描电子显 微镜(SEM)和傅里 叶变换红外(FT-IR)光谱分析仪对样品结构和形貌进行了表征。结果表明,制备的AgNWs/RG D材料具有与前驱 体不同的物理参数,有望在非线性光学、光电传感器和生物抑菌等方面有良 好的表现。     

GNRFET输运特性中的负微分电阻效应研究

利用密度泛函理论与非平衡格林函数相结合的数值分析方法,以均匀型和十字型两种不同类型的石墨烯纳米带作为沟道,研究了石墨烯纳米带场效应管(GNRFET)的负微分电阻效应。分析了不同类型GNRFET的端口输运性质:均匀型GNRFET具有良好的输运特性;十字型GNRFET由于中间的干破坏了原来两边缘的输运路径,其传输系数均不超过1。十字型GNRFET的输出特性具有明显的负微分电阻效应,且栅电压对此有调控作用。从传输谱的角度给出了GNRFET负微分电阻特性的理论解释和栅压调控的能量图,为微纳器件负微分电阻效应的研究提供了一定的理论依据。     

基于隧穿机理的石墨烯纳米带准一维器件设计北大核心

隧穿场效应晶体管（TFET）在低功耗领域具有很好的应用前景,以优化新型准一维TFET为目的,通过数值仿真研究了以石墨烯纳米带（GNR）为沟道材料的准一维TFET以及受器件尺寸和掺杂浓度控制的器件输运特性及开态和关态电流。以能带调控理论结合局域态密度与电流谱密度间的关系为手段对隧穿效应的机理进行了详细的探讨,分析了禁带宽度、栅覆盖范围、沟道长度和源漏掺杂浓度4个变量对输运过程的影响,进而确定了其对器件性能影响的变化趋势,并总结了相应原则,得到了有利于提高驱动能力、降低静态功耗以及满足数字电路一般性要求的准一维器件的设计策略。这一研究可为基于准一维材料的TFET的设计提供参考,推动基于平面材料的新型器件的发展。     

石墨烯/聚苯胺纳米复合材料的制备及防腐应用研究进展

导电聚苯胺(PANI)具有易合成、易掺杂等特点,石墨烯(GR)及石墨烯衍生材料具有较高的比表面积、良好的导电性、优异的防液体渗漏等物理和化学性质。两者的复合材料表现出优异的机械、电化学、防腐蚀等性能,引起了广泛的关注。介绍了石墨烯/聚苯胺纳米复合材料的制备方法、影响石墨烯/聚苯胺性能的主要因素以及石墨烯/聚苯胺纳米复合材料在防腐中的应用。系统总结了石墨烯/聚苯胺的防腐机理以及在不同基体涂料中的防腐改性,石墨烯的存在增加了腐蚀介质(如H2O和O2)渗透路径的曲折程度,减缓了金属腐蚀速度,从而提高涂料防腐效率。石墨烯/聚苯胺复合材料在防腐方面具有广阔的应用前景,对石墨烯/聚苯胺的复合状态、防腐机理、环境适应性的深入研究是未来该材料的发展方向。     

石墨烯纳米条带场效应管及构建电路研究

本文提出一种源漏轻掺杂异质栅结构石墨烯纳米条带场效应晶体管Graphene Nano Ribbon Field-effect Transistor(HMG-LDDS-GNR-FET),采用量子力学模型,研究其电学特性.仿真结果表明,与普通石墨烯纳米场效应晶体管(C-GNRFET)相比,HMG-LDDS-GNRFET的漏电流更小、开关电流比更大,电压增益也更大.该研究结果对碳基材料场效应管器件的设计有指导意义.     

硅纳米线纳米电子器件及其制备技术

硅纳米线由于特殊的光学及电学性能如量子限制效应及库仑阻塞效应等,在纳米电子器件的应用方面具有潜在的发展前景。介绍了采用电子束蚀刻技术(EB)、反应性离子蚀刻技术(RIE)、金属有机物化学气相沉积(MOCVD)等制备技术及场效应晶体管、单电子探测器及存储器、双方向电子泵及双重门电路等硅纳米线纳米电子器件的最新进展情况,并对其发展前景作了展望。     

A bilayer graphene nanoribbon field-effect transistor with a dual-material gate

This paper introduces dual-material gate (DMG) configuration on a bilayer graphene nanoribbon field-effect transistor (BLGNRFET). Its device characteristics based on nonequilibrium Green׳s function (NEGF) are explored and compared with a conventional single-material gate BLGNRFET. Results reveal that an on-off ratio of up to 10 is achievable as a consequence of both higher saturation and lower leakage currents. The advantages of our proposed DMG structure mainly lie in higher carrier transport efficiency by means of enhancing initial acceleration of incoming carriers in the channel region and the suppression of short channel effects. Drain-induced barrier lowering, subthreshold swing and hot electron effect as the key short channel parameters have been improved in the DMG-based BLGNRFET.     

Sentaurus® based modeling and simulation for GFET's characteristic for ssDNA immobilization and hybridization

The graphene field effect transistor (GFET) has been widely studied and developed as sensors and functional devices. The first report about GFET sensing simulation on the device level is proposed. The GFET's characteristics, its responding for single strand DNA (ssDNA) and hybridization with the complimentary DNA (cDNA) are simulated based on Sentaurus, a popular CAD tool for electronic devices. The agreement between the simulated blank GFET feature and the reported experimental data suggests the feasibility of the presented simulation method. Then the simulations of ssDNA immobilization on GFET and hybridization with its cDNA are performed, the results are discussed based on the electron transfer (ET) mechanism between DNA and graphene.     

A method to transfer an individual graphene flake to a target position with a precision of sub-micrometer

Graphene field-effect transistors have been intensively studied. However, in order to fabricate devices with more complicated structures, such as the integration with waveguide and other two-dimensional materials, we need to transfer the exfoliated graphene samples to a target position. Due to the small area of exfoliated graphene and its random distribution, the transfer method requires rather high precision. In this paper, we systematically study a method to selectively transfer mechanically exfoliated graphene samples to a target position with a precision of sub-micrometer. To characterize the doping level of this method, we transfer graphene flakes to pre-patterned metal electrodes, forming graphene field-effect transistors. The hole doping of graphene is calculated to be 2.16 × 10¹² cm^-2. In addition, we fabricate a waveguide-integrated multilayer graphene photodetector to demonstrate the viability and accuracy of this method. A photocurrent as high as 0.4 μA is obtained, corresponding to a photoresponsivity of 0.48 mA/W. The device performs uniformly in nine illumination cycles.     

基于石墨烯超材料的可调谐电磁诱导透明

提出了一种基于石墨烯超材料的可调谐电磁诱导 透明(EIT)结构,该结构是由长条-半圆环形状的石墨烯层和 介质基底组成。通过频域有限差分法研究了该结构的特性,研究结果表明,由于石墨烯条和 石墨烯半圆环之间发生相互 作用,产生较弱的杂化,从而可以观察到EIT透明窗口。更重要的是,通过控制门电压,改 变石墨烯的费米能级,可以 在较宽的频率范围内实现透明窗口的动态调谐。通过调节石墨烯的费米能级,在透射峰附近 群延迟接近0.4ps。同时还研 究了石墨烯条和半圆环间的距离、圆环的半径、方位角等几何参数对EIT效应的影响,这些 因素的改变对EIT 效应产生 了不同的影响。本文设计的超材料结构可应用于调制器和慢光器件等,对光开关、光存储等 新型器件的设计有重要的指导意义。     

Simple Ultrasonic-Assisted Clean Graphene Transfer

Clean graphene transfer has received widespread research attention, where most methods are focused on cleaning the upper surface of graphene to improve the transfer technique. However, the residue formation on the bottom surface of graphene is also inevitable; therefore, cleaning the bottom surface is crucial. In this study, we proposed an improved graphene wet transfer method using an ultrasonic processing(UP) step for etching copper(Cu). Using this method, the bottom surface can be cleaned eff...     

高性能激光诱导石墨烯压力传感器的研究

为了保证在低成本、易制备的前提下提高激光诱导石墨烯压力传感器的性能,设计了一种石墨烯压力传感器的放大结构。表征了激光诱导石墨烯压力传感器的表面结构,分析了表面多孔泡沫结构对压阻效应的影响,采用COMSOL软件对传感器放大结构的受力情况进行仿真分析,得到在外界压力下石墨烯层的受力情况。选用3D打印方法制备树脂材料放大结构基底,在低成本的同时兼顾了轻质、高精度、高机械强度等性能。测试结果表明,压强在5～20 kPa范围内时,该放大结构的灵敏度较无放大结构提高了约43%。     

Gate‐Controlled Energy Barrier at a Graphene/Molecular Semiconductor Junction

The formation of an energy‐barrier at a metal/molecular semiconductor junction is a universal phenomenon which limits the performance of many molecular semiconductor‐based electronic devices, from field‐effect transistors to light‐emitting diodes. In general, a specific metal/molecular semiconductor combination of materials leads to a fixed energy‐barrier. However, in this work, a graphene/C₆₀ vertical field‐effect transistor is presented in which control of the interfacial energy‐barrier is demonstrated, such that the junction switches from a highly rectifying diode at negative gate voltages to a highly conductive nonrectifying behavior at positive gate voltages and at room temperature. From the experimental data, an energy‐barrier modulation of up to 660 meV, a transconductance of up to five orders of magnitude, and a gate‐modulated photocurrent are extracted. The ability to tune the graphene/molecular semiconductor energy‐barrier provides a promising route toward novel, high performance molecular devices.