Electronic Properties of Liquid Semiconductor Solutions of Thallium and Tellurium

Abstract

Experimental data for the resistivity and Seebeck coefficient of liquid thallium-tellurium solutions have been analyzed in the light of the conventional equations for electronic structure and transport in solids. The behavior of p-type solutions can be described by the presence of deep acceptor levels which have an activation energy of 0.25db0.01 eV. The hole mobility n P in these solutions is nearly independent of composition with d In fj,p/d In T= -1.68±0.08 over a large range of T. Data are obtained about the variation of the concentration of acceptor states with composition. Preliminary information is also obtained about the energy of the band gap, and the mobility of w-type solutions. The results show that much of the observed behavior can be placed in the framework of conventional theoretical equations. We discuss some of the ways in which these equations may require significant modifications in the case of liquid semiconductors, and note how this would change our numerical results.

Molten Semiconductors for High Temperature Thermoelectricity

“…Cu 2 S, SnS, and PbS) which are all binary systems, but their Seebeck performances and optimum temperature range of operation are potentially too dissimilar to allow their coupling. However, it has been demonstrated that a binary molten material system with small composition variation around a stoichiometric compound could exhibit both p-and n-type characteristics, 24,28,43,48 enabling the potential use of the same materials for both legs of a cell. In addition, the evolution of the fundamental properties of binaries upon addition a.…”

“…Cutler and Mallon 24,25,27,28 focused on tellurium (Te)-based systems with addition of selenium (Se) and thallium (Tl). High temperature data for the Seebeck coefficient and electrical conductivity along with theoretical calculation of thermal conductivity provided some of the first Figures of Merit for molten semiconductor systems.…”

The Semiconduction in the Molten Tl‐CuTlTe2 System

“…The group of T1-X (X chalcogen element) systems is well known to be one of the most noticeable liquid semiconductors. A marked feature of these systems is that the thermoelectric power rapidly varies its sign from positive in the chalcogen excess region to negative in the metal excess region around the stoichiometric composition corresponding to TI,X (66.7 molyo T1) [3].…”

Bonding and electrical conduction in amorphous thallium-tellurium alloys

“…The liquid thallium-t,ellurium system has been studied extensively by Cutler and co-workers (Cutler and Mallon 1966, Cutler and Peterson 1970, Cutler 1971a, b, 1973, 1974 and by Enderby and Simmons (1969). Transport measurements provide clear evidence of the appearance of shortrange order a t the stoichiometric composition T1,Te.…”