Abstract
Oxygen adsorption and desorption processes are studied by surface photovoltage measurements. The surface barrier height is found to increase logarithmically with air pressure. The magnitudes of the barrier height measured under different pressures are shown to be about 0.5 V below the corresponding equilibrium values. This difference, as well as the observed variation of the barrier height with pressure, are accounted for by a simple rate equation based on the parameters of the oxygen-induced surface states derived independently from field effect measurements. A similar rate equation describes quite well the desorption of chemisorbed oxygen by recombination of photogenerated holes with electrons trapped in chemisorbed molecules. The effective cross section characterizing the desorption process is ≈ 10-27 cm2. Good agreement is obtained also between the measured and calculated variation of the surface photovoltage with light intensity.
Original language | English |
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Pages (from-to) | 169-180 |
Number of pages | 12 |
Journal | Surface Science |
Volume | 14 |
Issue number | 1 |
DOIs | |
State | Published - Mar 1969 |