Performance Enhancement of Black Phosphorus Field-Effect Transistors by Chemical Doping

In this letter, a new approach to chemically dope black phosphorus (BP) is presented, which significantly enhances the device performance of BP field-effect transistors for an initial period of 18 h, before degrading to previously reported levels. By applying 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), low ON-state resistance of 3.2 $\Omega \cdot \text {mm}$ and high field-effect mobility of 229 cm 2 /Vs are achieved with a record high drain current of 532 mA/mm at a moderate channel length of 1.5 $\mu \text{m}$ .