Local field emission spectroscopy of InSb micrograins

Abstract

Local electron density-of-state spectra and level parameters in indium antimonide (InSb) micrograins have been studied using a tunneling microscope in the field-electron emission regime. The activation energies (ψ) of electron levels and electron lifetimes (τ) on these levels have been determined based on the correspondence of current–voltage characteristics to the probabilities of emission. Several local electron levels in a near-surface region of intrinsic (i-InSb) micrograins are identified with ψ ∼ 0.73, 1.33, 1.85, 2.15, and 5.1 eV and τ ∼ 5 × 10^–8–3 × 10^–7 s, respectively. A physical model is proposed, according to which “light” electrons are localized due to the Coulomb interaction and their dimensional quantization takes place in the near-surface zone as determined by the effective mass, energy, and concentration of electrons and the radius of curvature of the micrograin surface.