Charge transfer from Cu inCu2Oepitaxially grown on MgO(001) by dc-reactive magnetron sputtering

Abstract

The Cu 2 O film is epitaxially grown on air-cleaved MgO͑001͒ by dc-reactive magnetron sputtering. From the reflection high-energy electron diffraction patterns two orientations are identified: ͑I͒ Cu 2 O(001)ʈMgO (001) and Cu 2 O͓100͔ʈMgO͓100͔ and ͑II͒ Cu 2 O(110)ʈMgO(001) and Cu 2 O͓11 0͔ʈMgO͓110͔. The charge transfer ⌬q Cu from Cu to O is also estimated by Auger electron spectroscopy. Both the Auger intensity ratio O/Cu and ⌬q Cu increased for the film annealed in O 2 , which indicates the as-deposited film is O deficient. From the annealed film ⌬q Cu for Cu 2 O is tentatively taken as 0.65e though still O deficient.