Reduced Vth Temperature Dependence in Bi-Dithiolbenzene in Parallel Arrangement-Impact of the Intermolecular Spacing

Abstract

Numerical simulations have been performed to study the effect of the temperature T on the electronic transport through a small group of molecular assembly system (MAS) by presenting I-V and G-V characteristics analysis for different geometry structures. The model involves 1,4-dithiolbenzene (DTB) (HSC6H4SH) molecules stacked in one dimension (1D). The MAS contains two DTB molecules packed in parallel geometrical arrangement. The relationship between the threshold voltage Vth and d the intermolecular spacing (which involves the -orbital interactions) is investigated when T ranges from 50 to 325 K. At fixed temperature, the system in the regime of stronger -interactions obtained with close DTB molecular unit (d=3.3Å), reduces Vth. Vth decreases approximately by 2.2 V when d changes from 3.3 to 6.9 Å. The temperature rise effect is another important factor that could reduce Vth . When T increases from 50 to 325 K, Vth decreases linearly, approximately by 1.2 V. More importantly, our simulation results correspond to L. Cai et al’s experimental results[24], the threshold voltage for switching molecular wire decreases as the temperature increases.