Modulating the electronic properties of silicene allotropes through the synergistic effect of different geometric configurations and edge hydrogenation

Abstract

Due to their excellent physical and chemical properties, Silicene nanomaterials have been widely used in optoelectronics and electronic devices. This paper studies the effects of period width and edge hydrogenation on the system stability and electronic properties of three different configurations of single-layer intrinsic tetra-octacyclic silicene nanoribbons (TO-SiNR) based on the density functional theory tight binding method (SCC-DFTB). It is found that the intrinsic TO-SiNRs with different configurations still maintain a long-range ordered low-energy stable structure after relaxation. Among them, regular-TO-SiNRs perform best, showing a direct narrow band gap semiconductor with a band gap of 0.553 eV at one-period width. Increasing the period width can effectively adjust the electronic band gap of TO-SiNRs so that the band gap gradually decreases and the electronic properties change from semiconductor to (semi)metal. In addition, the period width is also one of the key factors affecting the charge transfer of nanoribbons. Edge hydrogenation can lead to the distortion of the structure of horizontal- and vertical-TO-SiNRs and affect the charge transfer, thereby effectively adjusting its band gap and making it exhibit excellent semiconductor properties. These findings are expected to provide theoretical support for the design, synthesis, and performance regulation of new silicene semiconductor materials.