▎ 摘　　要

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.