ABSTRACT
In this paper, we report on the electronic structure of Cr-doped GaN and Mn-doped GaN observed by hard X-ray high-energy photoemission spectroscopy at the excitation energy of 5.95 keV. X-ray photoemission spectroscopy has been known as surface sensitive technique due to short mean free path of electrons at measured kinetic energies. This is serious problem in the case of epitaxial thin films, because surface cleaning procedures are not well established. However, very large escape depth at the energy of
5.95 keV would allow bulk sensitive measurements with negligibly small contribution from the surface [11-13].
