Hybrid diodes based on n-type Ge and conductive polymer doped by graphene oxide sheets with and without reduction treatment

Abstract

The authors present a hybrid diode based on n-type Ge and poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) having the reduced graphene oxide (RGO) or graphene oxide (GO) sheets. It is found that conductivity of RGO-doped PEDOT:PSS films increases with increasing the reduction temperature of GO sheets. The improvement of electrical conductivity is considered to mainly come from the carrier mobility enhancement. In addition, the ideality factor of n-type Ge/RGO-doped PEDOT:PSS diodes decreases with increasing the reduction temperature of GO sheets. The device-performance improvement originates from high-mobility hole transport combined with long-lifetime electron trapping in the RGO-doped PEDOT:PSS film. However, GO doping may lead to decreased conductivity, owing to the large number of the oxygen-related defects in GO sheets. The device-performance degradation originates from low-mobility hole transport combined with short-lifetime electron trapping in the GO-doped PEDOT:PSS film.