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O: Fachverband Oberflächenphysik

O 89: Poster Session - Oxide and Insulator Surfaces: Structure, Epitaxy and Growth

O 89.1: Poster

Mittwoch, 18. März 2020, 18:15–20:00, P2/1OG

High Pressure Oxidation of Copper - From Thin Films to Bulklike Materials — •Alexander Gloystein and Niklas Nilius — Institute of Physics, Carl von Ossietzky University Oldenburg, Germany

Copper oxidation at UHV-compatible O2 pressures only enables the formation of few-layer thick oxide films. In contrast, arbitrarily thick layers are produced by Cu deposition onto Au(111) followed by oxidation at 20-50 mbar O2. According to XPS, the Cu completely oxidizes to Cu2O in this case, while LEED reveals a highly uniform Cu2O(111) surface. The film morphology is governed by large hexagonal crystallites, being terminated by Cu-O six rings decorated with a sqrt3 shamrock structure known from bulk Cu2O(111). The latter indicates a high reducibility of the film, and even larger Cu aggregates emerge on the oxide surface upon vacuum annealing. The oxide reduction can also be followed in STM conductance spectra that evolve from a p-type behavior with a unique acceptor state above E(Fermi) to an almost stoichiometric conductance response. Further information on the Cu2O defect structure is obtained from temperature-controlled photoluminescence spectroscopy.