Strain engineering of electronic structure and mechanical switch device for edge modified Net-Y nanoribbons

Abstract

Net-Y is a new two-dimensional carbon structure, which has attracted research interest recently. Here, we study the relevant AB-type ribbons with edge modification, focusing on their strain controlling effects on their electronic structure and device characteristics. Intrinsic ribbons are metallic, but hydrogen or oxygen termination can transform them into semiconductors. Applying strain can effectively control the band gap size, resulting in a transition from an indirect band gap to a smaller direct band gap under appropriate strain, favorably to light absorbing. Strain can also change the work function of ribbons, especially for compressive strains, the work function is lowered significantly, which is beneficial to the improving of the field emission behaviors of ribbons. The analysis demonstrates that the change in band gap size is closely related to the variation of bonding and non-bonding composition between atoms with strain, while the change of work function is due to the variation of the attraction force and repulsion force between atoms upon strain. More interestingly, the strain can significantly regulates the <i>I</i>-<i>V</i> characteristic of device based on related ribbons. Therefore, a strain-gated mechanical switch with a very high current switching ratio <i>I</i><sub>on</sub>/<i>I</i><sub>off</sub> can be obtained by making it reversibly work between the “on” and “off” states with stretching and compressing ribbons, which is of great significance in developing the logic circuits for flexible wearable electronic devices.