Development of Optical Sensors Using Graphene

Abstract

This chapter demonstrates a new approach to manipulate and classify the graphene flake by choosing an optimal frequency of the applied electric field. In recent years, graphene has been the subject of increasing attention because it has a great potential for use in nano optoelectronics. Graphene is another novel nanomaterial and researchers have found a strong photoresponse near the graphene-metal interfaces. In addition graphene-based photodetectors can potentially be used for high-speed optical communications. The most common fabrication technique used for graphene-based nanostructures can be divided into two steps-first, electron beam lithography (EBL) is employed to pattern metal electrodes on a graphene. Then the resulting structures are etched by an oxygen plasma. However, plasma etching induces localization of charge carriers in graphene and changes its electronic properties. The disadvantages of EBL include its high cost and its low throughput. EBL machines are expensive and they also require substantial maintenance. Moreover, the patterning process takes a long time to complete because the electron beam is required to scan samples pixel by pixel. Discussion correlated the conductivity of the graphene flake with the frequency of the applied electric field. The theoretical prediction agrees well with the experimental results. With the ability to select high-conductivity graphene, the experimental result shows that graphene is a promising candidate for IR detection. The present study provides a systematic and reproducible method of selecting and separating high-conductivity graphene, which can also be used to manufacture novel IR nano sensors. © 2012 Elsevier Inc. All rights reserved.