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 mS*me=0.924(300KT)(nH1020cm-3)2/3[3(exp[|S|kB/e-2]-0.17)2/31+exp[-5(|S|kB/e-kB/e|S|)]+|S|kB/e1+exp[5(|S|kB/e-kB/e|S|)]] here mS* 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 10(20) cm(-3), T is the absolute temperature in K, S is the Seebeck coefficient, and k(B)/e = 86.3 mu V 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.

Automated summary

Engineering semiconductor devices requires understanding the effective mass of electrons and holes. By combining measurements of the Seebeck and Hall effects, the density of states effective mass can be determined in doped semiconductors at room temperature and above. This method provides a simple and independent estimate of effective mass, which is helpful in understanding and designing electronic structures, particularly for characterizing thermoelectric materials.