Hard X‐ray photoelectron spectroscopy study of core level shifts at buried GaP/Si(001) interfaces
Oleksandr Romanyuk, Oliver Supplie, Agnieszka Paszuk, Jan Philipp Stoeckmann, Regan G. Wilks, Jakob Bombsch, Claudia Hartmann, Raul Garcia‐Diez, Shigenori Ueda, I. Bartoš, Ivan Gordeev, J. Houdková, Peter Kleinschmidt, Marcus Bär, P. Jiřı́ček, Thomas Hannappel
Abstract
We present a study of buried GaP/Si(001) heterointerfaces by hard X‐ray photoelectron spectroscopy. Well‐defined thin (4–50 nm) GaP films were grown on Si(001) substrates with 2° miscut orientations by metalorganic vapor phase epitaxy. Core level photoelectron intensities and valence band spectra were measured on heterostructures as well as on the corresponding reference (bulk) substrates. Detailed analysis of core level peaks revealed line broadening and energetic shifts. Valence band offsets were derived for the films with different thickness. Based on the observed variation of the valence band offsets with the GaP film thickness and on the experimental evidence of line broadening, the existence of charge displacement at the GaP/Si(001) interface is suggested.