石墨烯量子点器件的制备与输运研究
发布时间：2019-02-11 19:16
【摘要】：量子点体系作为量子计算体系的一员由于其扩展性比较强,日益受到重视。通过自旋态的控制,半导体量子点体系有望制备成量子计算所需要的半导体芯片。本文以石墨烯材料为基础,加工制备了量子点器件,研究了石墨烯量子点的基本输运性质,使用CVD和机械剥离两种石墨烯进行了石墨烯量子点器件的制备,针对两种方式的石墨烯设计了不同的实验方案,对量产量子点器件进行了尝试。通过低温测试研究了石墨烯量子点的基本性质。在量子点器件制备之前我们通过拉曼光谱研究了受电子束辐照后,石墨烯在空气中的电学性质变化,为优化量子器件制备工艺,合理设计实验做了前期准备。文章内容主要有:1、通过拉曼光谱分析了石墨烯受电子束辐照后其电学性质随放置环境、时间的变化。实验中我们研究了辐照后石墨烯的电学性质与拉曼光谱性质。结果表明单层石墨烯易受到电子束辐照的影响。石墨烯拉曼光谱中D峰的出现表明电子束辐照在石墨烯晶格中引入了缺陷。石墨烯的载流子类型和电学电阻率通过电子束辐照能大范围的改变。这说明电子束辐照可以作为一种新的缺陷工程方法来改变石墨烯的性质。实验结果对包含电子束辐照的石墨烯纳米器件的制备和测量(如扫描电镜与电子束曝光)有很重要的指导意义,也为优化制备量子点器件实验步骤和工艺做了铺垫。2、通过大量实验获得了用电子束曝光制备量子点的工艺参数,如:束流、写场、调焦、剂量、临近效应的补偿。实现了20 nm量级以下的曝光精度和高达4:1的深宽比,为精确可控制备量子点结构打下基础。3、基于CVD石墨烯,结合紫外光刻与电子束光刻技术制备了石墨烯量子点器件。实验使用光刻、电子束蒸镀、氧等离子刻蚀、电子束曝光、反应离子刻蚀、引线等工艺来完成器件的制备,获得了成功制备量子点的关键参数,如:紫外光刻曝光时间、对准精度和显影时间,电子束蒸镀速率,氧等离子刻蚀功率,刻蚀时间,反应离子刻蚀时间,气体选择比,功率,和电子束光刻调试参量等。实现了石墨烯量子点的可控制备,并对量产石墨烯量子点器件进行了尝试。4、基于机械剥离的石墨烯用电子束曝光方法加工制备了石墨烯量子点器件,筛选出了势垒沟道电阻在25.8 k?至1000 k?的量子点器件,在低温下对它们进行了测试,实验测得了库仑阻塞效应和库仑菱形图,从中筛选出了合乎要求的石墨烯量子点器件。
[Abstract]:As a member of quantum computing system, quantum dot system is paid more and more attention because of its strong expansibility. By controlling the spin state, the semiconductor quantum dot system is expected to be used as a semiconductor chip for quantum computation. Based on graphene materials, quantum dot devices were fabricated. The basic transport properties of graphene quantum dots were studied. The graphene quantum dots were fabricated by CVD and mechanical stripping. Different experimental schemes have been designed for graphene in two ways, and quantum dot devices have been tried. The basic properties of graphene quantum dots were studied by low temperature measurement. Before the fabrication of QDs, we studied the changes of electrical properties of graphene in air by Raman spectroscopy, which was used to optimize the fabrication process of QDs and to design experiments reasonably. The main contents are as follows: 1. The electrical properties of graphene irradiated by electron beam were analyzed by Raman spectroscopy. In the experiment, we studied the electrical properties and Raman spectra of irradiated graphene. The results show that graphene monolayer is easily affected by electron beam irradiation. The appearance of D peak in graphene Raman spectra indicates that defects are introduced into graphene lattice by electron beam irradiation. The types of carriers and electrical resistivity of graphene vary widely by electron beam irradiation. This indicates that electron beam irradiation can be used as a new defect engineering method to change the properties of graphene. The experimental results are of great significance for the preparation and measurement of graphene nanodevices including electron beam irradiation, such as scanning electron microscopy and electron beam exposure. A large number of experiments have been carried out to obtain the technological parameters of the preparation of quantum dots by electron beam exposure, such as beam current, write field, focusing, dose and proximity effect compensation. The exposure accuracy of less than 20 nm and the aspect ratio of up to 4:1 are achieved. 3. Based on CVD graphene, the graphene quantum dot devices are fabricated by combining UV lithography and electron beam lithography. Photolithography, electron beam evaporation, oxygen plasma etching, electron beam exposure, reactive ion etching and lead wire were used to fabricate the device. The key parameters for the successful fabrication of quantum dots were obtained, such as the exposure time of UV lithography, Alignment accuracy and development time, electron beam evaporation rate, oxygen plasma etching power, etching time, reactive ion etching time, gas selection ratio, power, and electron beam lithography debugging parameters. The controllable preparation of graphene quantum dots has been realized, and an attempt has been made on the mass production of graphene quantum dots. 4. Graphene quantum dots were fabricated by electron beam exposure based on mechanical stripping graphene. The barrier channel resistance of 25.8 k? To 1000 k? The Coulomb blocking effect and the Coulomb rhombic diagram were measured. The graphene QDs were selected from the QDs.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O413;TN32
本文编号：2420028
[Abstract]:As a member of quantum computing system, quantum dot system is paid more and more attention because of its strong expansibility. By controlling the spin state, the semiconductor quantum dot system is expected to be used as a semiconductor chip for quantum computation. Based on graphene materials, quantum dot devices were fabricated. The basic transport properties of graphene quantum dots were studied. The graphene quantum dots were fabricated by CVD and mechanical stripping. Different experimental schemes have been designed for graphene in two ways, and quantum dot devices have been tried. The basic properties of graphene quantum dots were studied by low temperature measurement. Before the fabrication of QDs, we studied the changes of electrical properties of graphene in air by Raman spectroscopy, which was used to optimize the fabrication process of QDs and to design experiments reasonably. The main contents are as follows: 1. The electrical properties of graphene irradiated by electron beam were analyzed by Raman spectroscopy. In the experiment, we studied the electrical properties and Raman spectra of irradiated graphene. The results show that graphene monolayer is easily affected by electron beam irradiation. The appearance of D peak in graphene Raman spectra indicates that defects are introduced into graphene lattice by electron beam irradiation. The types of carriers and electrical resistivity of graphene vary widely by electron beam irradiation. This indicates that electron beam irradiation can be used as a new defect engineering method to change the properties of graphene. The experimental results are of great significance for the preparation and measurement of graphene nanodevices including electron beam irradiation, such as scanning electron microscopy and electron beam exposure. A large number of experiments have been carried out to obtain the technological parameters of the preparation of quantum dots by electron beam exposure, such as beam current, write field, focusing, dose and proximity effect compensation. The exposure accuracy of less than 20 nm and the aspect ratio of up to 4:1 are achieved. 3. Based on CVD graphene, the graphene quantum dot devices are fabricated by combining UV lithography and electron beam lithography. Photolithography, electron beam evaporation, oxygen plasma etching, electron beam exposure, reactive ion etching and lead wire were used to fabricate the device. The key parameters for the successful fabrication of quantum dots were obtained, such as the exposure time of UV lithography, Alignment accuracy and development time, electron beam evaporation rate, oxygen plasma etching power, etching time, reactive ion etching time, gas selection ratio, power, and electron beam lithography debugging parameters. The controllable preparation of graphene quantum dots has been realized, and an attempt has been made on the mass production of graphene quantum dots. 4. Graphene quantum dots were fabricated by electron beam exposure based on mechanical stripping graphene. The barrier channel resistance of 25.8 k? To 1000 k? The Coulomb blocking effect and the Coulomb rhombic diagram were measured. The graphene QDs were selected from the QDs.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O413;TN32
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