Low-frequency noise in polycrystalline semiconducting FeSi2 thin films

Abstract

Low-frequency noise measurements have been carried out at room temperature in polycrystalline semiconducting iron disilicide (β-FeSi2) thin film with the current I as a parameter. The power spectral density of the current fluctuations exhibits a 1/f behavior at low frequencies (f<100 Hz) and is proportional to Iβ (β<2). The temperature dependence of the conductivity shows that, at room temperature, the measured noise is related to a thermally activated transport mechanism, which satisfies the Meyer–Neldel rule. A noise theory has been developed on the basis of trapping-detrapping of holes of the valence band and the gap states taking into account mobility inhomogeneity across the thickness of the film. Using the experimental data of Hall, conductivity, and noise measurements, the noise model provides an assessment of the distribution of traps within the energy gap of the β-FeSi2 material.