(a) Drain current and applied gate voltage pulses during the first 5 min of a 2 h operation, and (b) stable 2 h operation. A gate voltage pulse (VG=0.5 V) was applied for 5 s with an interval time of 5 s between the successive pulses (VD=0.5 V), the device shown has channel dimensions of length 100 μm, width 10 μm and thickness 350 nm. The response times of the device are ∼5 ms for both device turn on and turn off. Frequency-dependent transconductance is included in the Supplementary Information (Supplementary Fig. 12).