Effective Mass from Seebeck Coefficient

Engineering semiconductor devices requires an understanding of the effective mass of electrons and holes. Effective masses have historically been determined in metals at cryogenic temperatures estimated using measurements of the electronic specific heat. Instead, by combining measurements of the Seebeck and Hall effects, a density of states effective mass can be determined in doped semiconductors at room temperature and above. Here, a simple method to calculate the electron effective mass using the Seebeck coefficient and an estimate of the free electron or hole concentration, such as that determined from the Hall effect, is introduced (Formula presented.) here (Formula presented.) is the Seebeck effective mass, n_H is the charge carrier concentration measured by the Hall effect (n_H = 1/eR_H, R_H is Hall resistance) in 10²⁰ cm⁻³, T is the absolute temperature in K, S is the Seebeck coefficient, and k_B/e = 86.3 μV K⁻¹. This estimate of the effective mass can aid the understanding and engineering of the electronic structure as it is largely independent of scattering and the effects of microstructure (grain boundary resistance). It is particularly helpful in characterizing thermoelectric materials.