The excellent TE performance of photoelectric material CdSe along with a study of Zn(Cd)Se and Zn(Cd)Te based on first-principles

Abstract

Zn(Cd)Se and Zn(Cd)Te are well known for their excellent photoelectric performance, however, their thermoelectric (TE) properties are usually ignored. By taking advantage of first-principles calculations, the Boltzmann transport equation and semiclassical analysis, we executed a series of thermal and electronic transport investigations on these materials. Our results show that CdSe has the lowest anisotropic thermal conductivity, k L , of the four materials, at 4.70 W m À1 K À1 (c axis) and 3.85 W m À1 K À1 (a axis) at a temperature of 300 K. Inspired by the very low lattice conductivity, other thermoelectric parameters were calculated in the following research. At a temperature of 1200 K we obtained a pretty large power factor, S 2 s, of 4.39 Â 10 À3 W m À1 K À2 , and based it on the fact that the corresponding figure of merit ZT can reach 1.8 and 1.6 along the a axis and c axis, respectively. We revealed the neglected thermoelectric potential of CdSe by means of systematic studies and demonstrated that it is a promising material with both excellent photoelectric performance and thermoelectric performance.

Superhigh flexibility and out-of-plane piezoelectricity together with strong anharmonic phonon scattering induced extremely low lattice thermal conductivity in hexagonal buckled CdX (X = S, Se) monolayers

“…The decrease in lattice thermal conductivity from CdS to CdSe can be analyzed from the increase in average atomic mass, decrease in phonon group velocity and the Debye temperature. The ultralow thermal conductivity obtained in CdSe monolayer is found to be one order of magnitude lower than that in its bulk structure (3.85 W m −1 K −1 ) [52]. The ultralow thermal conductivity has been observed in single layer CdX sheet which is very small compared to previously reported SnS (4.7 W m −1 K −1 ), SnSe (2.6 W m −1 K −1 ), GeSe (6. monolayers can be understood from their buckled structure which reduces the κ l by breaking the out-of-plane symmetry and increasing the exural phonon scattering [81,93].…”

“…The band gap of bulk CdS and CdSe semiconductors were reported to be 1.116 eV and 0.565 eV using GGA-PBE functional respectively [48,52]. Unlike transition metal dichalcogenides, the band gap remains direct even when it is thinned down to a monolayer [3].…”

Analysis of ternary AlGaX2(X = As, Sb) compounds for opto-electronic and renewable energy devices using density functional theory

“…In chalcogenides, Bi 2 Se 3 [6,7] semiconductor has been explored for thermoelectric applications. Scientists of the current era are very much interested in finding ternary semiconductors for the area of photoelectric technology [8] and thermoelectric technology [9], because they have good thermoelectric features, low effective mass, direct band gap and higher optical absorption coefficient [10,11].…”