Fabricating Two-Dimensional Metal Nanocrystal Arrays Using Pulsed-Laser Deposition and Focused Ion-Beam Technologies
- PDF / 578,147 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 53 Downloads / 188 Views
Fabricating Two-Dimensional Metal Nanocrystal Arrays Using Pulsed-Laser Deposition and Focused Ion-Beam Technologies Richard F. Haglund, Jr., Robert A. Weller, Cynthia E. Heiner1, Matthew D. McMahon2, Robert H. Magruder, III, Allen T. Newton, Liyong Shen and Leonard C. Feldman, Departments of Physics and Astronomy, Electrical and Computer Engineering and Mechanical Engineering, Vanderbilt University, Nashville TN 37235 U.S.A. 1 Department of Physics, University of New Hampshire, Durham, NH 0382403568 U.S.A. 2 Department of Physics, Drew University, Madison, NJ 07940 U.S.A.
ABSTRACT We describe recent experiments in which we attempted the initial steps for fabricating twodimensional arrays of metal nanocrystals. We use a commercial pulsed-laser deposition system in concert with a focused ion beam to attempt control over both lateral and vertical dimensions at the nanometer length scale. In our experiments, regular arrays of holes typically 80 nm in diameter were drilled in Si substrates using the focused ion beam. Silver atoms were then deposited onto these substrates by pulsed laser evaporation from a metallic target in high vacuum. Under certain conditions of substrate temperature, laser pulse repetition rate, and fluence, small silver nanoclusters form preferentially around the structures previously etched in the silicon surfaces by the focused ion beam. INTRODUCTION Ordered arrays of metal nanocrystals hold great promise for electronic and photonic technologies if their electronic, optical and magnetic characteristics can be designed. Single- and multilayer nanostructured materials based on metal nanoclusters or nanocrystals can be used to control capacitance in semiconductor gate oxides [1], to create optical materials with ultrafast temporal response [2] and enhanced optical nonlinearity [3] and to make advanced magnetooptical materials [4]. From these materials, one could make single-electron transistors [5] and other single-electron devices [6], sensitizers for defect-induced fluorescence [7], and optical conduits for efficient photodetectors [8]. In many of these applications, the spatial relationships and ordering of the nanocrystals are crucial to supporting a coherent response to optical, magnetic or electronic stimuli. Fabrication of regular nanocrystal arrays would also make it possible to study percolation phenomena, interactions among nanocrytals and elucidate coherence effects in photon, phonon and electron scattering and transport [9]. However, the fabrication of such devices requires extraordinary control of growth processes at nanometer length scales. Embedding metal nanocrystals in dielectric hosts presents a unique set of challenges. In this paper, we describe the use of the focused ion beam (FIB) to pattern substrates for subsequent growth of metal nanoclusters by pulsed laser deposition (PLD). The ultimate goal of this project is to encapsulate layers of self-organizing, spatially periodic nanocrystals in dielectrics (including transparent, conducting media such as indium-tin oxide). The key
Data Loading...
