Molecular simulation of metal-ZnO contact in ZnO piezoelectric nanogenerator

A molecular dynamics model has been developed to study the interfacial sliding dynamics in piezoelectric nanogenerator in atomic force microscope experiment. The molecular system includes a vertical semiconductor ZnO (0001) nanowire supported by a substrate and a Pt (111) metal tip. Simulation results show that the dynamic process of the Pt (111) tip sliding over the (0001) top surface of the ZnO nanowire, from the tensile side to the compressive side of the nanowire due to its lateral bending, involves the shear off of one monolayer of Pt atoms and the subsequent relaxation of the Pt (111) surface. However, no atomic inter-penetration or material transfer between the metal tip and the semiconductor material was observed. The calculated piezoelectric potential distribution due to the polarization of nanowire under bending is similar to the result derived from the continuum theory approach.