Photoemission of Holes and Electrons from Aluminum into Aluminum Oxide

The photoemission of both electrons and holes from aluminum into thin layers of ``plasma-grown'' aluminum oxide has been observed. The threshold energies for these processes are found to be 2.0±0.2 eV for electrons and 3.1±0.2 eV for holes. An approximate energy band diagram of the Al–Al2O3 interface based on these values is presented.