Evolution of Ag Nanocrystal Films Grown by Pulsed Laser Deposition

Abstract

We have conducted the first experiments under identical thermal, background, and surface preparation conditions to compare metal-on-insulator growth morphology in Pulsed Laser Deposition (PLD) and Physical Vapor Deposition (PVD). Such films deposited from a thermal vapor are known to exhibit a characteristic morphological progression beginning with isolated three-dimensional islands and ending with a percolating, continuous film that conducts electrically. We have studied this progression for Pulsed Laser Deposition, a technique that differs from PVD in that depositing species arrive in short bursts (<10 microseconds) with kinetic energy typically of 10-100 eV. Kinetic Monte Carlo (KMC) simulations that take into account only the pulsed nature of the flux predict that PLD films should advance to percolation with relatively less deposition compared with PVD under otherwise identical conditions. Our experiments, with PLD and PVD performed in the same chamber, reveal that PLD films actually require more deposition to reach percolation. We conclude that energetic effects are important in determining morphology evolution.