Coulomb blockade and charge transfer in InSb micrograins

Current-voltage characteristics and density-of-state spectra of indium antimonide (InSb) nano- and micrograins with conductivities close to intrinsic and electronic values have been studied using a tunneling microscope in the field-electron emission regime. Interpretation of the obtained data leads to the conclusion that the effect of current limitation, analogous to the Coulomb blockade in quantum dots, takes place in InSb micrograins. The results are explained in the framework of a model of multielectron recharge of the nanocapacitor formed in a near-surface layer of a micrograin where the charge is localized due to the Coulomb interaction between “ultralight” electrons in the bulk and on the uneven surface of the micrograin.