To the problem of Hall “mobility” in polycrystalline thin films with potential barriers

The peculiarities of the potential shape in polycrystalline films were considered. It was shown that the barrier height (φ_B) in sites (the place where three or more crystallites are connected) with respect to the concentration of boundary states (BS) was higher or coincided with the barrier height (φ_A) at the crystallite boundaries (CB). That is why the sites for majority charge carriers in films were “blocked down” and current transport along CB was not realized. If inversion of the conductivity type at CB was absent, the Hall potential was generated in quasi-neutral regions of crystallites and in barrier regions perpendicular to the current lines. If $\text{φ}{}_{\mathrm{A}}\text{+ E}{}_{\mathrm{F}}\text{<}\text{1}\text{2}\text{E}{}_{\mathrm{g}}$ the Hall potential coefficient (R_H) of the film is determined by the carrier concentration n₀ in quasi-neutral regions. In this case the activation energy of the Hall mobility was equal to the activation energy of the conductivity (σ_A). In the opposite case the inversion conductivity type takes place on CB. When the inversion regions are present near the barrier tops and conductivity is realized along CB, R_Hp ～ (N_cN_v/n₀)^-1 exp (E_g?φ_B/kT) and μ_Hp ～ exp (?φ_B?φ_A/kT), where E_g is the band gap, N_c, N_v are the effective density of states in the conduction and valence bands.