Measuring the work function of TiO₂ nanotubes using illuminated electrostatic force microscopy

The varying nature of TiO₂ nanotube work function as a function of illumination wavelength has been determined using illuminated electrostatic force microscopy. The dark work function was found to be 4.902 eV, with the largest change in work function due to illumination being at 300 nm, which was higher than the work function for bulk TiO₂ (4.899 eV). The change in work function due to illumination arises from the flattening of the energy bands at the surface due to charge migration