Adjusted surface work function of InN films annealed at vacuum and at high-pressure N2 conditions

Annealing studies were performed to investigate the effects of heat treatment on InN thin films by changing the annealing condition from vacuum to high pressure N2. A significant variation of ∼400 meV in the surface work function was observed for InN films. The basic principles of Kelvin probe measurement revealed that the surface band bending ESBB is crucial in investigating the significant changes of surface work function on the InN. The stoichiometric ratio imbalance of In and N was indirectly determined to be the main cause of the variation in band bending by analyzing the X-ray diffraction and energy dispersive X-ray measurements. Thus, the annealing treatment could be an effective method to adjust the surface work function of InN by changing the annealing condition from vacuum to high pressure N2.

► Three different annealing methods were performed for InN films.
► The surface work function could be adjusted by annealing.
► Significant changes in the work function of InN films were observed.