In Situ Electrical Studies of Ozone Based Atomic Layer Deposition on Graphene

Abstract

In this study, we present in-situ electrical studies of back-gated graphene field-effect transistors (GFETs) exposed to ozone at room temperature. Here, we compare the effect of the ozone exposure on transport characteristics in two different environments using a vacuum probe station with static vacuum and an atomic layer deposition (ALD) chamber having a dynamic environment with continuous nitrogen purge. We observed that in both the cases there is a p-type doping in graphene upon exposure to ozone, but, there is a significant difference in the ozone exposure time required to witness a noticeable effect on the transport properties, with the dynamic environment requiring a longer ozone treatment period. The observed effect on graphene devices was found to be reversible under vacuum suggesting a physisorption process. We also demonstrate top-gate GFETs on chemical vapor deposited (CVD) graphene using 10 nm ALD Al2O3 as gate dielectric deposited with the ozone functionalization approach.