SGER: Surface and Sub-Surface Imaging at Nanometer Scales Using Picosecond Thermoacoustic Microscopy

SGER：使用皮秒热声显微镜进行纳米尺度的表面和次表面成像

• 批准号: 9910823
• 负责人: Arunava Majumdar
• 金额: $ 8.41万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9910823&HistoricalAwards=false
• 关键词: SGER; Surface; Sub; Imaging; Nanometer

ABSTRACTProposal Number: CTS-9910823Principal Investigators: A. MajumdarThe ability to manipulate matter and to observe and control physical and biological phenomena at nanometer scales is providing researchers with rich opportunity for basic science as well as new technology. One of the most important aspects of this research is the ability to observe objects and phenomena with nanometer scale spatial resolution. The scanning tunneling (STM) and the atomic force microscopes (AFM) and, in general, the whole class of scanning probe microscopes (SPMs), have made it possible to image single atoms and observe single biological molecules on a solid surface. The current SPMs, however, fail to address some fundamental needs in nanotechnology, namely: (i) the ability to image objects below the surface, i.e. in three dimensions, with nanometer vertical and lateral resolution; (ii) the ability to perform spectroscopy in order to identify the chemical content of the material. Imaging in three dimensions is extremely important because of the following reasons: (a) microelectronics chips are becoming increasingly multilayered; (b) biological molecules have three-dimensional structure and function; (c) nanophase materials are generally three dimensional. The ballistic electron emission microscope (BEEM) [1] is able to image and perform electron spectroscopy below the surface to a distance of about 100-200 A. However, it needs a metal and a semiconducting material to operate. Magnetic resonance imaging using the AFM [2,3] can provide a three-dimensional picture, although one needs to perform experiments at very low temperatures ( 1 K) to obtain sub-micron resolution. To image objects in three dimensions, there are two possible approaches: (i) to either emit some form of radiation and measure its time-resolved scattering (elastic or inelastic) at a certain point in space (eg. ultrasonic imaging); or (ii) to confine resonance excitation to a certain location by an external field (eg. nuclear magnetic resonance). This project will use the first approach. It will combine two techniques - scanning probe microscopy for high lateral resolution and picosecond thermoacoustics for high vertical resolution - to obtain three-dimensional images with nanometer-scale resolution.

在纳米尺度上操纵物质、观察和控制物理和生物现象的能力为研究基础科学和新技术提供了丰富的机会。该研究最重要的方面之一是能够以纳米尺度的空间分辨率观察物体和现象。扫描隧道显微镜（STM）和原子力显微镜（AFM），以及总的来说，整个扫描探针显微镜（SPMs）的出现，使得在固体表面上对单个原子成像和观察单个生物分子成为可能。然而，目前的SPMs未能满足纳米技术的一些基本需求，即：(i)对表面以下物体成像的能力，即三维，具有纳米级的垂直和横向分辨率；（ii）进行光谱学以鉴定材料的化学成分的能力。由于以下原因，三维成像非常重要：(a)微电子芯片正变得越来越多层；(b)生物分子具有三维结构和功能；(c)纳米相材料通常是三维的。弹道电子发射显微镜（BEEM）[1]能够在地表以下成像并执行电子能谱，距离约为100-200 a。然而，它需要金属和半导体材料来操作。使用原子力显微镜（AFM）进行磁共振成像[2,3]可以提供三维图像，尽管需要在非常低的温度（1 K）下进行实验以获得亚微米分辨率。要在三维空间中对物体成像，有两种可能的方法：(i)发射某种形式的辐射，并在空间的某一点测量其时间分辨散射（弹性或非弹性）。超声成像);或（ii）用外场将共振激励限制在某一位置。核磁共振)。本项目将使用第一种方法。它将结合两种技术——高横向分辨率的扫描探针显微镜技术和高垂直分辨率的皮秒热声学技术——来获得纳米级分辨率的三维图像。