Largely Enhanced Mobility of MoS2 Field-Effect Transistors by Optimizing O2-Plasma Treatment on MoS2

2-D layered MoS
₂
is considered as a promising candidate for novel nanoelectronic devices in recent years. However, a large number of structural defects in MoS
₂
have been widely reported, which will greatly degrade the electrical performance of MoS
₂
devices. In this work, it is demonstrated that the structural defects in MoS
₂
can be repaired by a reasonable-power O
₂
-plasma treatment, e.g., a 30-W O
₂
-plasma treatment on MoS
₂
results in an enhanced carrier mobility of 69.82 cm
²
/Vs, which is 2.5 times higher than that of the untreated devices, a reduced subthreshold swing of 131.27 mV/dec, and a high ON/OFF current ratio of 3.18×10
⁶
. These are attributed to the fact that the suitable-power O
₂
-plasma treatment can effectively repair the structural defects in MoS
₂
and reduce the scattering centers, improving the electrical performance of MoS
₂
FETs. However, a high-power O
₂
plasma will generate high-energy oxygen ions to bombard the MoS
₂
, introducing more new defects and deteriorating the electrical performance of MoS
₂
FETs.