The study of ambipolar behavior in phosphorene field-effect transistors

Abstract

The electrical characteristics of phosphorene field effect transistors (FETs) were investigated with the two-dimensional (2D) numerical simulation. In this study, it is found that the Schottky barrier plays an important role in the ambipolar transfer characteristics of phosphorene-based FETs. It is demonstrated that when the barrier heights are equal between electron and hole doping, the ambipolar current output dominates across the whole bias range. In the meantime, the saturation leakage current output of the transfer characteristic is only determined by the number of phosphorene layers or the bandgap rather than the Schottky barrier height between phosphorene and metal contact. The ambipolar behaviors become more pronounced as the channel lengths of transistors are decreased, all the geometric and material parameters are taken into account to improve the ambipolar output and understanding its underlying mechanisms. The presented results open the path to design phosphorene-based logic device, photo detector with low dark current for both electronic and optoelectronic applications.