Influences Of Encapsulated Hfo2 Film On The Performance Of Graphene Filed Effect Transistors

Although the sensitivity of the traditional electrolyte-gated graphene FET is high, the graphene channel is easy to be polluted because of the direct contact between graphene and electrolyte, which leads to the poor stability of the device and not reusable. Ion sensitive field-effect transistors based on graphene (G-ISFET) with top dielectric layer could address the problems. However, deposing dielectric layer on graphene channel is a kind of doping process which debases the performance of G-ISFET. Therefore, the influences from the top dielectric layer in G-ISFET are important and should be studied. In this work, a bottom gate G-ISFET is designed and fabricated, which uses graphene as channel and insulating layer HfO2 as the protective film of graphene. Besides, through a series of electrical characterization, the influence of the deposited HfO2 top layer on graphene FET is analyzed, and the device's characters as pH sensor is further explored.