In this work, the structural, electronic and optical properties of novel atomically thin systems based on germanene and antimonene nanocomposites have been investigated by means of density functional theory.

The structural, electronic and optical properties of the graphene hybrid with stanene, the tin counterpart of graphene, are investigated by means of density functional calculation with the observation of band gap opening and enhanced visible light response. The lattice mismatch between graphene and stanene is taken into consideration and several stacking methods for model construction are proposed to study the possible effects. The Dirac feature can be observed in this bilayer system with relatively stronger interlayer interaction than weak van der Waals forces, which is ascribed to the unsaturated p orbital of stanene. Despite the mutual semi-metal nature of graphene and stanene, it is significant to note a band gap opening and the electrical neutrality of the bilayer. The combination of high carrier mobility of graphene and the excellent spin Hall effect of stanene is expected to coexist in the bilayer structure. In addition, we found that the stanene monolayer has a relatively lower work function than graphene and more importantly, it exhibits more pronounced optical absorption than graphene. The results indicate that a graphene/stanene heterobilayer will facilitate the performance of stanene related spintronic devices and is therefore a good candidate for photoelectronic devices.

Recent reports focus on the experimental preparation of metal monolayer-stanene which is a zero-gap semiconductor with buckled honeycomb structure. Owing to the outstanding properties of stanene, its promising applications in nanoelectronics are widely concerned and studied. Using the first-principles calculations, we investigate the adsorption behavior of CO, NH 3 , H 2 O, H 2 S, O 2 , NO, and NO 2 molecules on a stanene sheet based on the energetics, charge transfer, and work function. We determine the optimal adsorption sites of small molecule on the stanene sheet and the styles of molecule doping, and discuss the interaction mechanism between the molecule and stanene. The results indicate that the sensing performance of stanene is superior to other 2D materials such as silicene and germanene. It is found that CO, O 2 , NO, and NO 2 molecules act as charge acceptors, whereas NH 3 , H 2 O, and H 2 S molecules serve as charge donors. For nonpolarized molecules, the molecule−stanene interaction is mainly ascribed to the electrostatic attractions effect. In contrast, for polarized molecules, the covalent interaction plays a critical role in the process of adsorption. We further investigate the variation of the work function for small molecules' adsorption on stanene. The work function calculations exhibit various responses to the different molecules, which indicate that the Schottky barrier height can be effectively tuned by the selective adsorption of these small molecules. The nontrivial sensitivity and selectivity of stanene show that it has a potential application in the field of gas sensors and high performance catalysts.

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