Non-equilibrium electronic properties of ultra-thin SiC NWs influenced by the tensile strain

Abstract

The effect of the tensile strain on non-equilibrium electronic properties are studied for the ultra-thin SiC NWs (NWs) with different diameters. Results show that the equilibrium conductance fluctuates with the strain, and the maximum decreases with the increase of the size. Essentially, strong conductance originates from large electron transmission and delocalized electronic states. For I–V characteristics, the tensile strain affects significantly the growth rate and intensity of the current. Under any biases, the strongest current appears in late strain (0.7136) for the single-atom chain, while in the starting strains (e.g. 0.1584, 0.2504) for thicker NWs. The tensile strain would weaken the current of thicker NWs. The mechanical stretching contributes to valuable negative differential resistance (NDR) effect, which appears in middle and late stretching stages such as 5408, 0.7136 and 0.8472 for these three SiC NWs, respectively. Furthermore, NDR effect occurs at more strains and presents multistage features as the diameter of NW increases. The conductance waves with voltage. Such fluctuation deepens and show a more concentrated range with the increased size of NWs. The conductance at closer strains changes with the bias in a relatively close range. From structural evolution, when the NWs are fully extended under tensile strain without structural damage, the necking or the formation of single atom chains, the corresponding conductance and current are stronger, deriving from delocalized electronic states. This work provides an approach to get access to valuable NDR effect and strong backing in promising applications of nano piezoelectric electronics for ultra-thin SiC NWs.