Tuning the rod diameter of ZnO nanorods on porous silicon by incorporating graphene

In this research, graphene was incorporated into the ZnO nanorods (NRs) growth in two different ways to enlarge the rod diameter of ZnO NRs on porous silicon (PS) substrates. We etched the P-type Si (1 0 0) wafer to form the PS layer in solution with HF and C2H5OH and H2O2 for appropriate time. Then, ZnO NRs with and without incorporating graphene were grown with solgel/hydrothermal methods on top of the PS substrates, respectively. To characterize the graphene incorporated ZnO NRs on PS substrates, multiple material analyses including field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, photoluminescence, IV curves were used to study the graphene-incorporated ZnO NRs. Results indicate that ZnO NRs with larger diameters could be viewed with graphene included into the ZnO NR growth in two different ways. Furthermore, higher defect concentrations could be observed for the graphene-contained NRs. In addition, the ZnO/PS contact exhibited rectifying electrical behaviors without graphene addition but non-rectifying electrical behaviors with graphene incorporation. Tuning ZnO NRs growth on PS substrates with graphene is promising for future ZnO NRs/Si-based device applications.