Study and suppression of ambipolar effect in multilayer phosphorene tunnel field effect transistors using double gate structure

We present a comprehensive study of ambipolar effect in multilayer phosphorene tunnel field-effect transistors (TFETs). Phosphorene is a promising 2D material with tunable bandgap and high mobility but ambipolarity limits many of its potential applications. We explain the ambipolar effect with energy band diagram which results in undesirable off state drain current. This work uses an in-house built simulator and suggests a technique to suppress the ambipolar current by using different gate oxide materials. However, this method has a trade-off that it reduces on-current too. Therefore, in this paper, we present a novel double gate structure of multilayer phosphorene TFETs which not only minimizes the off-current but also sustains the on-current at its desired level. The proposed design is very efficient in suppressing ambipolarity up to a certain number of layers. The simulated results are presented in tabular form which would be helpful for any further study on ambipolarity of phosphorene TFETs. The proposition can be extended to other 2D material TFETs too where ambipolarity limits device performance.