Mechanism of the effects of low temperature Al2O3 passivation on graphene field effect transistors

The origin of the device instability of chemical vapor deposited graphene metal oxide semiconductor field effect transistor has been investigated while varying the characterization time scale from milliseconds to a few tens of seconds. When oxygen diffusion to the graphene interface was suppressed with Al2O3 passivation layer, the hysteresis activated with a, time scale over a few tens of seconds was reduced significantly at both electron and hole branches of current-voltage curves. However, a fast charge trapping process occurring within a few milliseconds was not affected by the passivation and became a dominant mechanism of hysteresis. (C) 2012 Elsevier Ltd. All rights reserved.