Bond rupture and energy GAP engineering of graphene layers epitaxially grown on silicon carbide: ab-initio calculations

• Grant number: 09/14404-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: November 01, 2009
• End date: February 28, 2011
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Adalberto Fazzio
• Grantee: Thiago Barros Martins
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

One of the searches of nanoscience is the discovery of new materials at the nanoscale that may results in applications such as in nanodevices. The expectation of the scientific community to build nanodevices, similar to those in microelectronics, moves and promotes the field of nanoelectronics. In this scenario, graphene has played an important role in the area. Its synthesis was obtained independently by 3 different groups. The reason for such importance is related to the intriguing electronic properties that it presents. One of the community challenges is getting a production method that is able to provide graphene sheets on a large scale for industrial using. Epitaxial growth of graphene on a substrate of silicon carbide has proven to be a promising method. This method provides graphene layers with high crystallinity and electronic properties observed for graphene mono-layers. From the graphene film grown on the substrate, electronic nanodevices can be "designed" using lithography techniques. However, the final use of such devices depends on two factors: (i) the chemical decoupling of all circuit substrate and (ii) control of the energy GAP that defines the character of the semiconductor circuit (such as a diode). Both issues can be addressed through the use of appropriate dopants. For example, gold atoms adsorbed between the substrate and the graphene sheet can lead to broken connections between the substrate and graphene. While the use of boron atoms adsorbed on the graphene sheet can produce energy GAPs whose magnitude should depend on the boron atoms concentration. (AU)