Effect of grain size on thermal transport in post-annealed antimony telluride thin films

Abstract

The effects of grain size and strain on the temperature-dependent thermal transport of antimony telluride (Sb 2 Te 3) thin films, controlled using post-annealing temperatures of 200°C to 350°C, were investigated using the 3-omega method. The measured total thermal conductivities of 400-nm-thick thin films annealed at temperatures of 200°C, 250°C, 300°C, 320°C, and 350°C were determined to be 2.0 to 3.7 W/m • K in the 20 to 300 K temperature range. We found that the film grain size, rather than the strain, had the most prominent effect on the reduction of the total thermal conductivity. To confirm the effect of grain size on temperature-dependent thermal transport in the thin films, the experimental results were analyzed using a modified Callaway model approach.

Effect of Grain Size and Film Thickness on the Thermoelectric Properties of Flexible Sb2Te3 Thin Films

“…Measurements of Seebeck coefficients and electrical conductivity were conducted by a DC four-terminal method (ZEM-3, ULVAC-RIKO) from 30 to 250°C. e effects of grain size and film thickness on the temperature-dependent thermal transport of Sb 2 Te 3 thin films were investigated using theoretical modelling based on the Callaway theory [2,13] and a modified phonon scattering mechanism proposed by Park et al [2]. Figure 1 shows the XRD spectra of Sb 2 Te 3 thin films.…”

“…In this work, the theoretical modelling of the thermal conductivity of the lms was investigated using a phonon transport model, which is dependent on the relaxation time [13]. e expression for the expected lattice thermal conductivity (K L ) is given as follows [2,13]:…”

“…In recent decades, there has been extensive research on thermoelectric materials and devices [1,2]. In general, the performance or properties of thermoelectric materials depends on the temperature gradient (ΔT) and the dimensionless figure of merit (ZT).…”

“…Antimony telluride (Sb 2 Te 3 ) is considered one of the best thermoelectric materials since it can achieve a relatively high figure of merit at room temperature [2,8,9]. in film deposition techniques, namely, coevaporation, pulsed laser deposition, magnetron sputtering, and electrodeposition, have already been used for fabricating Sb 2 Te 3 .…”

“…Both the Seebeck coefficient and electrical resistivity are linear functions of the reciprocal of film thickness. In addition, Park et al [2] studied the strain-and grain size-dependent thermal conductivity of Sb 2 Te 3 thin films prepared by RF magnetron sputtering and postannealing treatment. e modified Callaway model approach was used to analyse how the grain size affects thermal transport in Sb 2 Te 3 thin films.…”