Bandgap radiation induced photodesorption from V2O5 powder and vanadium oxide surfaces

Abstract

A mass-spectrometric analysis of photodesorption from V2O5 power and oxidized vanadium surfaces shows that carbon dioxide is the only desorbing species under UV irradiation. The threshold wavelength for this process for V2O5 powder is about 520 nm, which corresponds to a photon energy of 2.35 eV. The experimental data also indicates that, (1) the thermal induced and photon-induced desorptions of CO2 from the oxidized vanadium sample behave quite differently, (2) carbon concentration on the sample surface was found to decrease under prolonged exposure to UV radiation, and (3) the CO2 desorption signal depends linearly on the incident photon intensity. This linearity further supports the bandgap photon-induced desorption model, which requires electron-hole pair production as the initiating step.