HALL-EFFECT MEASUREMENTS TO CALCULATE THE CONDUCTION CONTROL IN SEMICONDUCTOR-FILMS OF SNO2

Hall effect measurement is one of the most powerful methods for obtaining information about transport mechanisms in polycrystalline semiconductor compounds that constitute the basis for understanding the sensing function of semiconductor gas sensors. The presence of grain boundaries represents the essential difference between single-crystal and polycrystalline semiconductors. The boundaries are important because they generally contain fairly high densities of interface states which trap free carriers from the bulk of the grains. In this paper the grain size of the semiconductor (calculated by the XRGA technique) and Hall effect measurements are used in order to obtain conduction-band profiles. Depending on the preparation method (reactive sputtering, electron beam, serigraphy), three types of conduction control can be distinguished. Similar results are obtained from analysis of the material microstructure.