The Masses of Free Holes and Electrons in Tellurium

Abstract

The transverse effective hole masses of tellurium samples with p = 1 0 I 6 to 1018 0n1-3 have been determined from Faraday rotation measurements at 10, YO, and 300 K. The comparison of the experimental values with the calculated Faraday masses enables to prove the validity of various band models for large k. The model presented by Bnngert gives the best fit. Thus the strong temperature dependence of the hole mass determined from transport measurements by many authors is shown to be due to the nonparabolicity of the valence band. At higher temperatures (300 to 400 K) also the free electrons contribute to the Faraday effect. This rotation could be explained by Bangert's model, too. Die transversale Lochermasse wurde fur Telliirproben mit Locherkonzentrationen zwischen lo1& und 10I8 c~I -~ aus Faradayeffckt-Messungen bei 10,90 und 300 K bestimmt. Die experimentellen Faradaymassen wurden mit den nach den bekannten Bandmodellen berechneten verglichen. Dabei ergab das von Bangert angegebene Model1 besonders fur groBe k-Werte die beste Ubereinstimmung. AuBerdem erklart sich so die starke Temperaturabhangigkeit der Lochernmssen, die von vielen Autoren bei Transport.messungen gefunden wurde. Sie wird durch die Nichtparabolizitat des Valenzbandes verursacht. Bei hohen Ternperaturen (300 bis 400 K) tragen such die freien Elektronen zum Faradayeffekt bei. Diese Drehung konnte eberifalls mit dem Modell von Bangert beschrieben nerden.

Te/CdTe and Al/CdTe Interfacial Energy Band Alignment by Atomistic Modeling

“…Electron and hole effective masses from separate DFT bulk calculations for the CdTe and Te layers are reported in Table (see Supporting Information (SI) for details of the bulk calculations). The values were found to be in decent agreement with previous computational and experimental literature − after the implementation of the Hubbard-U correction. The effective masses were used for quantifying certain parameters within the numerical device simulations found in the proceeding section.…”

Charge Mobility and Recombination Mechanisms in Tellurium van der Waals Solid

“…38 The intrinsic density of charge carriers is given by for a three-dimensional (3D) semiconductor, 39 with m e * and m h * being the effective masses of electrons and holes taken from previous reports, respectively. 12,15 Furthermore, k B denotes the Boltzmann constant, T the temperature, and ℏ the reduced Planck constant. Note, that Liu et al 11 reported that the interchain electronic coupling of Te atomic wires is comparable to the intrachain electronic coupling.…”

“…Terms containing the factor n i 2 take into account the generation of electron–hole pairs by deviation from the thermodynamic equilibrium carrier density n i through absorption of blackbody radiation, thermal excitation, or impact ionization by sufficiently energetic intrinsic thermally excited charge carriers . The intrinsic density of charge carriers is given by for a three-dimensional (3D) semiconductor, with m e * and m h * being the effective masses of electrons and holes taken from previous reports, respectively. , Furthermore, k B denotes the Boltzmann constant, T the temperature, and ℏ the reduced Planck constant. Note, that Liu et al reported that the interchain electronic coupling of Te atomic wires is comparable to the intrachain electronic coupling.…”

“…As a 1D van der Waals material, Te has been widely studied for its electronic structure, − optical properties, ,, Hall conductivity, and extrinsic mobility in p-type Te. − Very recently, it gained attention due to its high thermoelectric figure of merit. , The aforementioned studies on conductivity and mobility have mostly been performed at low temperatures (∼77 K), with externally doped samples and using contact measurements. , Therefore, it is of great interest to study its intrinsic optoelectronic properties without external doping and at temperatures close to ambience.…”

In-situ resonant band engineering of solution-processed semiconductors generates high performance n-type thermoelectric nano-inks

“…We can explore the effect of shifting E F on the Seebeck coefficient by modeling it as a function of the position of E F in the film (Supplementary Note 4 and Supplementary Figs. 23-26) [64][65][66] . In traditional TE materials, wherein the E F lies close to the band edge or deep within the band, a decrease in the charge carrier concentration would predict an increase in the Seebeck coefficient.…”