Characterization of Single Phase Nanometric Cu2O Films Grown by Thermal Oxidation in the Range of 600 to 950° C in an Atmosphere with Low Oxygen Content

Abstract

High-quality single phase p-type nanometric films of cuprous oxide with controllable properties were produced by thermal oxidation of copper thin films from 600 to 950°C in a nitrogen (N2) atmosphere with 5ppm of oxygen content at atmospheric pressure. The resistivity of films was of 300 Ω-cm for samples produced at high temperatures and decreased below of 80 Ω-cm for samples grown at lower temperatures. The minimum hole concentration was 8×1014 cm-3 for films grown at high temperatures and increased up to 8×1015 cm-3 for low temperatures, the corresponding Hall mobilities vary in the range of 20-45 cm2/V-s with the best values for samples grown at high temperatures. The observed electrical behavior is related to the structural lattice defects controlled mainly by the oxidation kinetics process under low oxygen atmosphere concentration conditions. When the oxidation temperature was decreased some traces of the cupric oxide phase was observed, the formation of this phase was apparent because of the characteristic reddish color of the Cu2O films changes to the blackish aspect for the tenorite phase. The Cu2O phase was assessed through the XRD and Raman characterization techniques. This work demonstrates that the thermal oxidation method produces Cu2O nanometric films with enough quality to be used in electronic device applications.