Fabrication of Nanometer-Scale Sensors on Scanning-Probe Microscope Tips

扫描探针显微镜尖端纳米级传感器的制造

• 批准号: 0080393
• 负责人: Daniel Ralph
• 金额: $ 30万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0080393&HistoricalAwards=false
• 关键词: Fabrication; Nanometer; Scale; Sensors; Scanning

New classes of scanning sensors and probes, with minimum feature sizes of approximately 10 nm, will be made on the tips of scanning-probe microscopes using a new stencil technique, which allows the direct deposition of nanostructures onto non-planar surfaces. These sensors will be used to image the nm-scale functional properties of electronic devices and materials with greatly improved resolution and sensitivity, as compared with existing techniques. They should also allow several new forms of scanning microscopy, providing images of quantities not currently accessible. The new probes will be supplied to and optimized in cooperation with several of the leading young researchers pursuing scanned-probe microscopy. Examples of the types of sensors and the research subjects that will be investigated include: (1) magnetic field sensors. Single ferromagnetic nanoparticles will be deposited on the tips of atomic-force-microscope probes, for use in magnetic force microscopy (MFM). Compared to conventional MFM probes, they will provide improved spatial resolution and less magnetic perturbation on the sample, in local studies of magnetic and superconducting devices. Giant-magnetoresistance sensors composed of a ferromagnetic / non-magnetic / ferromagnetic trilayer will also be made with 10-nm feature sizes for imaging the spatial distributions of magnetic fields. (2) bow-tie antennas for near-field optical microscopy. Metallic pads in a bow-tie configuration will be deposited at the tips of optical fibers, to serve as an antenna for optical photons, and thereby make a nm-scale optical source for use in ear-field scanning optical microscopy. This is predicted to allow greatly improved optical transmission efficiency (10's of % efficiency, as compared to 10 -3 for aluminum-coated tapered-optical-fiber sources), thus permitting improved spectroscopy and time-resolved measurements. At the same time, these antennas should provide improved spatial resolution, on the order of 10 nm rather than approximately 50 nm for conventional sources. (3) scanning single-electron-transistor electrometers. A metal particle approximately 10 nm in diameter will be deposited on the tip of a scanning tip, in tunneling contact with 2 electrodes, to make a single-electron tunneling device that will serve as a sensitive electrometer. These will be employed to probe electric-field configurations of semiconductor and metal devices while they are in operation, the effects that impurities on metal surfaces have in producing local changes in the work function, and the microscopic origin of offset charges and charge noise in single-electron tunneling devices. (4) gated scanning-tunneling-microscope tips. Two electrically separate metal electrodes will be deposited in close proximity on the same insulating tip. One will be used for conventional scanning tunneling microscopy, while an independent voltage can be applied to the second electrode so that it acts as a gate to shift the local electrostatic potential of the sample under study. This will provide a new capability for characterizing the quantum-mechanical levels participating in electron tunneling, within quantum dots and single-molecule devices. Other new types of sensors or probes that may be fabricated on the 10 nm scale include scannable thermometers, heaters, and refrigerators, sources and detectors of microwave radiation, and electronic spin-filters for use in spin-resolved scanning tunneling microscopy.

新型扫描传感器和探针的最小特征尺寸约为10纳米，将使用一种新的模板技术在扫描探针显微镜的尖端上制造，这种技术允许在非平面表面上直接沉积纳米结构。与现有技术相比，这些传感器将用于对电子设备和材料的纳米级功能特性进行成像，其分辨率和灵敏度大大提高。它们还应该允许几种新形式的扫描显微镜，提供目前无法获得的数量的图像。这些新探针将提供给几位从事扫描探针显微镜研究的领先年轻研究人员，并与他们合作进行优化。传感器类型和研究课题的例子包括：(1)磁场传感器。单铁磁性纳米颗粒将沉积在原子力显微镜探针的尖端，用于磁力显微镜（MFM）。与传统的MFM探针相比，它们将在磁性和超导器件的局部研究中提供更高的空间分辨率和更少的样品磁扰动。由铁磁/非磁/铁磁三层组成的超大磁阻传感器，其特征尺寸为10nm，用于成像磁场的空间分布。(2)用于近场光学显微镜的领结天线。金属衬垫呈领结形状，将沉积在光纤的尖端，作为光学光子的天线，从而制成用于耳场扫描光学显微镜的纳米级光源。预计这将大大提高光传输效率（10%的效率，相比之下，铝涂层锥形光纤光源的效率为10 - 3%），从而允许改进光谱学和时间分辨测量。同时，这些天线应该提供改进的空间分辨率，在10纳米的数量级上，而不是传统光源的大约50纳米。(3)扫描单电子晶体管静电计。直径约10纳米的金属颗粒将沉积在扫描尖端，与两个电极隧道接触，制成一个单电子隧道装置，将用作灵敏静电计。这些将用于探测半导体和金属器件在运行时的电场结构，金属表面上的杂质对产生局部功函数变化的影响，以及单电子隧道器件中偏移电荷和电荷噪声的微观起源。(4)门控扫描-隧道-显微镜尖端。两个电分离的金属电极将在同一绝缘尖端上近距离沉积。一个将用于传统的扫描隧道显微镜，而一个独立的电压可以施加到第二个电极，使其作为一个门，以移动所研究样品的局部静电电位。这将为描述量子点和单分子器件中参与电子隧穿的量子力学水平提供新的能力。其他可能在10纳米尺度上制造的新型传感器或探针包括可扫描温度计、加热器和冰箱、微波辐射源和探测器，以及用于自旋分辨扫描隧道显微镜的电子自旋滤波器。