Electrochemical gating of CVD graphene–ZnO based tansistor

Abstract

Two dimensional semimetal (graphene) and metal oxide (ZnO) is an interesting combination of materials for optoelectronic applications. A schottky junction formed between graphene and ZnO layers and this junction properties can be used for applications like sensors, phototransistors, UV detectors etc. The schottky junction can be tuned applying a suitable gating voltage across the junction. In this work Graphene - ZnO heterostructure was first fabricated and subsequently electrochemically gated transistors were made. Graphene was grown by chemical vapour deposition method on copper substrate and then transferred to Si/SiO2.substrate. Hexagonal ZnO nanorods were grown over high quality single layer graphene using two electrode electro-deposition method. This heterostructure was electrochemically gated by using LiClO4 : PEO electrolyte. The electric double layer will induce large amount of charge carriers in graphene - ZnO heterostructure and causes the gating effect. The characterizations of the heterostructure along with the interesting properties of the devices are discussed.