Conducting-tip atomic force microscopy for injection and probing of localized charges in silicon nanocrystals

A conducting-tip atomic force microscopy (AFM) is utilized to inject localized charges in an ensemble of closely packed nanocrystalline Si dots prepared by plasma decomposition of SiH4. A noncontact-mode topography imaging carried out to probe the charging effect indicates an increase in the apparent height of the Si nanocrystal. A generalized tip-sample force interaction model is also developed to quantitatively evaluate the deposited charge. The study prescribes that the presence of surface charges might result in an overestimation of the actual height of an object measured by AFM, which could be nontrivial for a nanomaterial in particular.