SGER: Near-Field-Controlled Nanoscale Coating of Functional Thin Films for Nanodevices

目的：各种微/纳米器件已被设计和制造，以执行复杂的功能，在力学，电子学和光子学。功能薄膜的纳米级涂覆是许多重要器件应用中的主要加工步骤之一。为了提高微/纳米器件的性能和可靠性，开发纳米级可控表面涂层技术和建立纳米级表面工艺的基本理解具有巨大的推动力。该研究的总体目标是开发一种新型的近场光化学过程，用于功能薄膜的自控沉积。本项目的目标是：1）模拟纳米器件的纳米尺度局部光增强; 2）检测近场增强光化学; 3）在微/纳米机电系统上存款类金刚石（DLC）薄膜采用激光辅助化学气相沉积（CVD）技术制备MEMS/NEMS器件;以及4）表征DLC涂层MEMS/NEMS的摩擦学性能。在拟议的研究中，可见光和/或紫外线激光将用于照射纳米结构，如液体或气体前体中的纳米尖端，MEMS/NEMS设备。由于近场效应，在尖锐尖端/边缘附近的高度局部限制和增强的电磁（EM）波可以用于液体或气体前体的光学分解，以用于薄膜的自控沉积。该工艺结合了传统激光化学沉积和光学近场效应的优点，从而可以实现高度空间定位的沉积。实验证明，在苯溶液中，脉冲准分子激光在W纳米针尖上沉积类金刚石薄膜存在近场效应，在W纳米针尖上沉积的类金刚石薄膜具有与针尖尖锐度相关的近场效应，并沿针尖尖端沿着存在相位梯度。这启发我们提出了一个基于近场的自沉积过程，这是很好地控制在nanosscales.Intellectual优点：拟议的研究是一个新的领域，涉及近场光学。本研究将利用光学近场作为纳米尺度化学反应的局部能量源。其意义是双重的：首先，它是一种可控的表面工艺，将表面涂层扩展到3-D器件结构。对高度空间受限的电磁波沉积纳米材料的基本认识具有重大的科学意义。其次，这是一种直接满足纳米器件尖端和边缘涂层需求的技术，特别是作为纳米级广泛磨损应用的自润滑和保护涂层。更广泛的影响：这项研究将通过在具有广泛应用的3D器件结构上涂覆功能薄膜的效率、成本和定位精度的革命性变化而造福社会，如半导体，光子学，电子产品和消费品，对社会各个层面产生深远影响。研究成果将通过网站和各种会议传播。一名来自代表性不足的少数民族的研究生和两名本科生将参与拟议的项目。一个动画套件显示MEMS/NEMS的应用和纳米薄膜沉积的基本思想将开发和分发给K-12教师和学生在年度公开研讨会。

Objective: Various micro/nanodevices have been designed and fabricated to perform complex functions in mechanics, electronics and photonics. Nanoscale coating of functional thin films is one of the major processing steps in many important device applications. There is tremendous impetus to develop a nanoscale controllable surface coating technique and establish fundamental understandings of nanoscale surface processes for the purpose to improve micro/nano-device performance and reliability. The overarching goal of the proposed research is to develop a novel near-field photochemical process for self-controlled deposition of functional thin films. The project objectives are to 1) simulate nanoscale local light enhancement by nanodevices; 2) detect near-field-enhanced photochemistry; 3) deposit diamond-like carbon (DLC) films on micro/naonelectromechanical system (MEMS/NEMS) devices using laser-assisted chemical vapor deposition (CVD); and 4) characterize tribological performance of DLC-coated MEMS/NEMS.Innovative method: In the proposed research, a visible and/or UV laser will be used to irradiate nanostructures such as nanotips, MEMS/NEMS devices in liquid or gaseous precursors. Due to the near-field effects, highly locally confined and enhanced electromagnetic (EM) waves in the vicinity of sharp-tips/edges can be used for optical decomposition of liquid or gas precursors for a self-controlled deposition of thin films. The process combines the advantages of conventional laser chemical deposition and optical near-field effects, so that highly spatially-localized deposition can be achieved. Our recent work experimentally proved that there are near-field effects in the pulsed excimer laser deposition of DLC films on W nanotips in a benzene solution.A tip-sharpness-dependent coating of DLC on W nanotips and a phase gradient along the tip apexes were observed. This inspires us to propose a near-field-based self-deposition process which is well controlled at nanoscales.Intellectual Merit: The proposed research is a new field involving near-field-optics. The proposed research is to utilize optical near-field as local energy sources for nanoscale chemical reactions. The significance is two-fold: First, it is a controllable surface process which extends surface coating to 3-D device structures. Fundamental understanding of nanoscale material deposition by highly spatially-confined EM wave is of major scientific interest. Second, it is a technique directly addressing the need for coatings on sharp tips and edges of nanodevices, especially as self-lubricating and protective coatings for extensive wear applications at nanometric levels.Broader Impacts: This research will benefit the society by revolutionizing the efficiency, cost, and positioning accuracy of coating functional thin films on 3-D device structures which have wide applications such as semiconductor, photonics, electronics, and consumer products, having a profound impact on all societal levels. Research outputs will be disseminated via a website and through different conferences. One graduate student from an underrepresented minority and two undergraduates will work on the proposed project. An animation kit showing the applications of MEMS/NEMS and basic ideas on the thin film deposition at the nanoscale will be developed and distributed to K-12 teachers and students in annual public seminars.