Graphene oxide thin film field effect transistors without reduction

Pristine graphene oxide thin film field effect transistors were fabricated on Si substrates without an additional reduction process. Graphene oxide with an optical band gap of 1.7 eV showed p-type semiconducting behaviour in air and ambipolarity under vacuum. The temperature dependence of conductance confirmed these semiconducting characteristics. I–V characteristics were well fitted to a variable range hopping model with 2 + 3 dimensionality, in good contrast to the 2D fitting in the reduced graphene oxide.