Observing variations in carrier-scattering mechanisms of polycrystalline bismuth through its temperature-dependent properties

Abstract

This study has investigated variations in the carrier scattering mechanisms of polycrystalline bismuth based on the temperature dependence of its transport coefficients across a range of temperatures from 10 to 300 K. A measurement of the continuous temperature dependence of the Hall coefficient revealed the characteristic extremes of its temperature-based parameters to be less than 50 K. The results demonstrated a clear variation in the component of the scattering mechanism pertaining to acoustic deformation. Furthermore, the temperature dependencies of carrier density, mobility, chemical potential, and band gap energy were also comprehensively investigated to determine their influence on carrier transport. The information obtained in this study is quite relevant for the realization of the carrier transport of Bi nanowire. The carrier transport of the wire exhibits a mean free path that is equivalent to the wire diameter and has been expected to introduce a quantum effect, thus enhancing the thermoelectric performance.

Temperature dependence of resistivity and temperature coefficient of a single-crystal bismuth nanowire based on the varying scattering mechanism

“…The scattering parameter r i,t rapidly varied from −1/2 to +1/2 with λ bulk,i,t /d wire = 0 to α. 35,36,39) Based on this relationship, we estimated each scattering parameter r i,t for various values of the wire diameter d wire , crystal orientation toward the wire length t, and temperature T. Regardless, the parameters α and β are introduced in Eq. ( 3) to determine the scattering parameter r i,t , which was undetermined in the current model.…”

“…Additionally, the resistivity, magnetoresistivity, Seebeck coefficient, Hall coefficient, and Nernst coefficient have been measured using bulk polycrystalline with a grain size of several micrometers. [34][35][36] Based on the measurement results and the developed model, the variation in the scattering mechanism was caused by the acoustic deformation potential scattering in the lower-temperature regions with certain grain boundaries caused by the substantially longer mean free path than the grain size. Thus, a prominent variation in the scattering mechanism can be obtained using a nanowire whose mean free path is restricted by the wire diameter.…”