XPS study of gas sensitive SnO/sub 2/ thin films

SnO/sub 2/ is a dominant material in production of solid state gas sensors. However, till now the nature and forms of chemisorbed species on its surface remain debatable. In this report we present the results of XPS study of the SnO/sub 2/ thin films after various treatments in vacuum, oxygen, and both dry and humid atmospheres (T/sub an/=25-600/spl deg/C). SnO/sub 2/ films were deposited by spray pyrolysis method. We analyzed the changes of the SnO/sub 2/ surface stoichiometry, energy positions of main XPS peaks, and concentration of adsorbed particles. On the base of obtained results the assumptions on the nature of absorbed species on the SnO/sub 2/ surface have been made.