The mechanical design of graphene nanodiodes and nanotransistors: geometry, temperature and strain effects

Abstract

The technique of laminating one or several layers of graphene on a substrate and making a bridge of small dimensions and then measuring the changes in the electrical properties of the circuit obtained from this connection has raised the hopes of miniaturizing electronic devices even further. Due to the importance of this subject and the need to mechanically design such systems before signal-taking, in this paper, the effects of geometry, temperature and mechanical deformations on the mechanical properties of graphene nanodiodes and nanotransistors have been studied by employing the molecular dynamics method. A tensile test has been used as a suitable means of measuring the mechanical properties of suspended graphene sheets and graphene nanodiodes, and a virtual indentation test has been employed for zigzag and armchair transistors. After validating the method used by comparing it to former works, the most important finding for the diode case reveals that by increasing the rectification angle from zero to 90°, the modulus of elasticity drops from 1.092 to 0.79 TPa for certain dimensions; which is a reduction of 27.65%. In the graphene transistor, the modulus of elasticity increases with the increase of transistor width. Nevertheless, in stark contrast to armchair transistors, the difference between the mechanical properties of zigzag transistors and suspended graphene becomes greater as the transistor length increases. In general, the square transistor enjoys the highest modulus of elasticity and, thus, the best stiffness; while such square graphene sheets are ruptured at lower strains and stresses, compared to other graphene transistor dimensions.