Interface formation between tris„8-hydroxyquinoline… aluminum and ZnO nanowires and film

摘要

The energy level alignments at the interface between trisu00028-hydroxyquinolineu0003 aluminum u0002Alq3u0003 andnZnO nanowires and thin film were studied with in situ x-ray and ultraviolet photoemissionnspectroscopy. The changes of work functions, highest occupied molecular orbitals, and core levelsnwere measured with step-by-step deposition of Alq3 on each ZnO substrate. Although bothnsubstrates show similar electronic structures, a larger interface dipole is induced at the interfacenbetween Alq3 and ZnO nanowires. This results in the reduction of the electron injection barrier atnthe interface of Alq3 /ZnO nanowires. Thus, the ZnO nanowire substrate is expected to show betternperformance than that of ZnO film when used as a cathode. We discussed the different interfacendipole formation at each interface. © 2010 American Institute of Physics. u0004doi:10.1063/1.3531812