Light induced electrostatic force spectroscopy: Application to local electronic transitions in InN epifilms

Abstract

A technique based on electrostatic force microscopy in which light is used to change the charge states of the local region in a solid is introduced and demonstrated. This technique provides a unique feature that it can be used to probe local electronic transitions of a solid in a submicron scale. As an illustration, it has been applied to study local electronic structure in InN epifilms. Combining with atomic force microscopy, it is found that surface state density in the dale region is larger than that in the pinnacle region and an electron accumulation layer does exist on the surface. In addition, the magnitude of the surface band bending obtained for the regions with different surface states is consistent with the result measured by other techniques. We point out that light induced scanning electrostatic force spectroscopy is a very useful tool to probe the local electronic transitions of a solid in a submicron scale with high sensitivity.