Prediction of sp3 -tized Diamond like Structure Induced by Hydrogenation of Grarphene Exhibiting Diamond Properties

Abstract

We studied how multilayer graphene can undergo transformation into sp3 structure by using density functional theory (DFT) method and predicted diamond-like properties in multilayered sp3 structures at varying thickness. Herein, hydrogenation of multilayer graphene at the top and bottom surfaces induce a sp2 to sp3 transition and as a result, a diamond-like structure can be obtained. Surface hydrogenation reduces the transition barrier of multilayer graphene due to the low stability of hydrogen passivated graphene layer caused by unpaired electrons. As the number of sp2 layer becomes smaller the hydrogen coverage becomes relatively large, and this drives the transformation of the sp2 structure into sp3 configured structure with diamond-like properties at the bulk region. To validate our findings, electronic and mechanical properties of sp3 multilayer graphene were calculated by varying the number of carbon layers and the stacking orientation of the sp3 structure. The sp3 structure exhibited various electronical and mechanical properties indicative of a diamond material, except that the electrons of conduction band were mainly distributed at the hydrogenated surface. This is due to the top and bottom surface stabilization through termination with hydrogen; reconstructing the sp2 carbon into sp3. The ultrathin structure can be used in applications where absolute thinness in the material plays a vital role.