• PDF / 240,165 Bytes
• 11 Pages / 584.957 x 782.986 pts Page_size
• 97 Downloads / 213 Views

DOWNLOAD

REPORT

---

Device and sensor miniaturization has enabled extraordinary functionality and sensitivity enhancements over the last decades while considerably reducing fabrication costs and energy consumption. The traditional materials and process technologies used today will, however, ultimately run into fundamental limitations. Combining large-scale directed assembly methods with highsymmetry low-dimensional carbon nanomaterials is expected to contribute toward overcoming shortcomings of traditional process technologies and pave the way for commercially viable device nanofabrication. The purpose of this article is to review the guided dielectrophoretic integration of individual single-walled carbon nanotube (SWNT)- and graphene-based devices and sensors targeting continuous miniaturization. The review begins by introducing the electrokinetic framework of the dielectrophoretic deposition process, then discusses the importance of high-quality solutions, followed by the site- and type-selective integration of SWNTs and graphene with emphasis on experimental methods, and concludes with an overview of dielectrophoretically assembled devices and sensors to date. The field of dielectrophoretic device integration is filled with opportunities to research emerging materials, bottom–up integration processes, and promising applications. The ultimate goal is to fabricate ultra-small functional devices at high throughput and low costs, which require only minute operation power.

I. INTRODUCTION

Cost reduction, device functionality, and energy efficiency are the major driving forces in semiconductor and microelectromechanical system miniaturization. Over the years, progress in miniaturization and the appearance of new functional materials has led device feature sizes to venture into the nanometer size regime.1,2 At the same time, it is reasonable to expect that some of the “workhorse” materials and fabrication techniques used today, such as silicon (Si) and photolithography, respectively, will ultimately run into fundamental physical limits. It is therefore necessary to pursue alternatives to currently successful top–down fabrication processes, such as the directed assembly of high-symmetry low-dimensional materials, while always maintaining the ability of largea)

Present address: Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 Address all correspondence to these authors. b) e-mail: [email protected] c) e-mail: [email protected] This paper has been selected as an Invited Feature Paper. DOI: 10.1557/jmr.2011.186 J. Mater. Res., Vol. 26, No. 13, Jul 14, 2011

scale assembly. To this end, in this article, the dielectrophoretic integration of individual carbon nanomaterials, namely single-walled carbon nanotubes (SWNTs) and graphene, for large-scale device and sensor assembly is reviewed as a possible route to achieve this goal. Dielectrophoresis (DEP) is a phenomenon in which a force is exerted on a suspended particle, generally in a liquid, when it is subject