Paper TF-WeM10
Epitaxial Growth of Ag/MgO(001) and Ag/Si(111) by Pulsed Laser Deposition for Use as an Alternative to Single Crystal Metallic Substrates

Wednesday, December 10, 2014, 11:00 am, Room Makai

Single crystal metal substrates are often used as platforms for growth. Epitaxial films are potentially cheaper starting points for chemical synthesis single crystal substrates. We report on the epitaxial growth of thin silver films in the crystallographic orientations (001) and (111) using pulsed laser deposition (PLD). The films were deposited on MgO(001) and Si(111) substrates to a thickness of 40 nm at 150 °C and 170 °C, respectively. For the first 2-4 nm, growth was three-dimensional at which point a gradual transition to two-dimensional growth occurred, as monitored by reflection high-energy electron diffraction (RHEED). Scanning tunneling microscopy (STM) was used to show that the surface roughness was less than 5 Å in 100×100 nm² for either orientation. Photoelectron spectroscopy (PES) was used to probe the chemical state of the films. The positions of the Ag 3d_5/2 and Auger MNN peaks were used to calculate the Auger parameter to be 726.3 Ev, which corresponds to metallic Ag. These films may be inexpensive replacements for single crystal Ag substrates in certain applications.