Two-dimensional bipolar junction transistors

Abstract

Recent development in fabrication technology of planar two-dimensional (2D)\nmaterials has brought up possibilities of numerous novel applications. Our\nrecent analysis has revealed that by definition of p-n junctions through\nappropriate patterned doping of 2D semiconductors, ideal exponential I-V\ncharacteristics may be expected. However, the theory of 2D junctions turns out\nto be very much different to that of the standard bulk junctions. Based on this\ntheory of 2D diodes, here we construct for the first time, a model to describe\nthe 2D Bipolar Junction Transistors (2D-BJTs). We derive the small-signal\nequivalent model, and estimate the performance of a 2D-BJT device based on\nGraphone as the example material. A current gain of about 138 and maximum\nthreshold frequency of 77GHz, together with a power-delay product of only 4fJ\nper 1um lateral width is expected at an operating voltage of 5V. Also, we\nderive necessary formulae and a new approximate solution for continuity\nequation in the 2D configuration, which have been verified against numerical\nsolutions.\n