OPTIMIZED DEGENERATE CHEMICAL DOPING TOWARD P-WSe2 FET

Abstract

Here in this work we have presented a chemical way of doping few layers (thickness ~12nm) WSe2 to get a high performance p-type field effect transistor (FET). For this, AuCl3 mix with acetonitrile is used as a chemical dopant for WSe2 FET. Upon the reaction of AuCl3 with WSe2 the Au+3 reduces to stable Au0 particle leaving behind a p-WSe2 FET. The effect of chemical doping on WSe2 with AuCl3 as a dopant is confirmed by changing of Pd and WSe2 barrier from Schottkey to Ohmic-like behavior. In this case the doping helps in reduction of contact resistance by thinning the width of the barrier which helps in tunneling the hole from Pd contact to WSe2 as a result the hole mobility of our device is increases from 0.26 cm2/V.S to 149 cm2/V.S at 10 mM concentration of AuCl3 which is the highest achievement ever by doping in TMDC materials. Here we have also investigated a stable and optimized value of doping concentration to get highly p-doped WSe2 device. From the results we have concluded that at 10 mM concentration of AuCl3 we can get a 104 time enhancement in ON current a 1000 times increase in conductivity and a shift of 75V in the threshold voltage after doping. Chemical doping of WSe2 with AuCl3 chemical dopant is highly stable and efficient way for achieving highly doped P-WSe2 FET, and this study will prove promising to realize highly efficient complementary device.