title: Surface engineering of reduced graphene oxide for controllable ambipolar flash memories.
abstract: Tunable charge-trapping behaviors including unipolar charge trapping of one type of charge carrier and ambipolar trapping of both electrons and holes in a complementary manner is highly desirable for low power consumption multibit flash memory design. Here, we adopt a strategy of tuning the Fermi level of reduced graphene oxide (rGO) through self-assembled monolayer (SAM) functionalization and form p-type and n-type doped rGO with a wide range of manipulation on work function. The functionalized rGO can act as charge-trapping layer in ambipolar flash memories, and a dramatic transition of charging behavior from unipolar trapping of electrons to ambipolar trapping and eventually to unipolar trapping of holes was achieved. Adjustable hole/electron injection barriers induce controllable Vth shift in the memory transistor after programming operation. Finally, we transfer the ambipolar memory on flexible substrates and study their charge-trapping properties at various bending cycles. The SAM-functionalized rGO can be a promising candidate for next-generation nonvolatile memories.
authors.affiliation: Department of Physics and Materials Science and Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong SAR.
authors.forename: Su-Ting
authors.initials: ST
authors.lastname: Han
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhou
authors.forename: Prashant
authors.initials: P
authors.lastname: Sonar
authors.forename: Huaixin
authors.initials: H
authors.lastname: Wei
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Yan
authors.forename: Chun-Sing
authors.initials: CS
authors.lastname: Lee
authors.forename: V A L
authors.initials: VA
authors.lastname: Roy
keywords: ambipolar; charge-trapping behavior; flash memory; reduced graphene oxide; self-assembled monolayer; work function