The long term change of the CuInSe2 surface composition under low energy hy
drogen ion beam implantation at an increased substrate temperature was stud
ied with in situ X-ray photoelectron spectroscopy (XPS). A removal of surfa
ce oxides as well as of surface contaminations due to the treatment could b
e observed. After storage in air, no reformation of oxides, such as SeO2 an
d In2O3, was detected. Ion beam hydrogenation causes considerable post-grow
th changes in the defect population. Initially in p-type CuInSe2, the dista
nce between the valence band maximum (VBM) and the Fermi level increased. A
reactivation of oxygen-passivated V-Se, the production of additional selen
ium vacancies as well as changes in the active V-Cu population, might expla
in these observations. At elevated substrate temperatures, the hydrogen ion
beam produces an In-rich surface near to Cu2In4Se7 with a slightly reduced
Se-content, independent of the initial surface composition. (C) 2001 Elsev
ier Science B.V. All rights reserved.