Cross-sectional transmission electron microscopy of thin graphite films grown by chemical vapor deposition

• Published in: Diamond and related materials Vol. 19; no. 2; pp. 143 - 146
• Main Authors: Colby, Robert, Yu, Qingkai, Cao, Helin, Pei, Steven S., Stach, Eric A., Chen, Yong P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2010; Elsevier
• Subjects: Chemical vapor deposition; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross sections; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Film thickness; Fullerenes and related materials; diamonds, graphite; Graphene; Graphite; Ion beams; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Specific materials; Structure and morphology; thickness; Surface and interface electron states; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Thin films; Transmission electron microscopy; Thin films; Transmission electron microscopy; Graphene; Chemical vapor deposition; Graphite; Ultrathin films; Electronic properties; Polycrystals; Layer thickness; Ion beams; CVD; Multilayers; Electron beams; Analysis method; Nickel; Defect structure; Damage
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2009.06.001

Graphene has been the subject of an extraordinary upsurge of interest due to its intriguing properties and potential applications. Recent work has shown that excellent electronic properties are exhibited by large-scale ultrathin graphite films, grown by chemical vapor deposition on a polycrystalline metal and transferred to a device-compatible surface. The properties of such multilayered graphene films could depend strongly on film thickness and uniformity. Unlike the other common methods for analysis in the literature, cross-sectional transmission electron microscopy (TEM) would provide direct, straightforward analysis of film thickness and quality, as well as provide a means to investigate specific defect structures (e.g. wrinkles). However, this approach has not often been pursued due to the sensitivity of graphite to the electron and ion beam damage in such a procedure. Here, an approach to creating cross-sectional TEM samples using a focused ion beam lift-out method is presented, along with the resulting TEM images of thin graphite films and several wrinkle defects. Samples removed from as-grown films on polycrystalline nickel and films removed from measured devices are presented. The benefits and limitations to this approach are discussed.