Pulsed Laser Deposition of C₆₀ Thin Films with Atomically Smooth Surface

Abstract

Pulsed laser deposition was found to be a novel method for the fabrication of high-quality C 60 thin films with extremely smooth surfaces. The irradiation of a pulsed KrF excimer laser beam onto a C 60 powder target induced the formation of a plasma plume when the laser energy fluence was 40 mJ/cm 2 and higher. The ablated species were condensed onto a substrate in the form of thin film. Thin films deposited at laser energy fluences in the narrow range between 40 mJ/cm 2 and 50 mJ/cm 2 were confirmed to have a single phase of C 60 solid from the Raman scattering and optical absorption spectra as well as from the chromatography of benzene extract of the films. With increase of the laser energy fluence over 50 mJ/cm 2 , the deposited films included increasing amounts of photodecomposed components and, consequently, varying physical properties. Atomic force microscopy revealed atomically smooth surfaces of C 60 thin films laser-deposited at laser energy fluences between 40 mJ/cm 2 and 50 mJ/cm 2 .