High-Quality SnSe₂ Single Crystals: Electronic and Thermoelectric Properties

Abstract

The high-quality SnSe 2 single crystal was successfully synthesized using the temperature gradient method. N-type characteristic and strong anisotropic transport properties of SnSe 2 single crystal were exhibited between ab-plane and c-axis. At 673 K, the power factor (PF) value along ab-plane is 3.43 -1 while it along c-axis is . The ratio between thermal conductivities along ab-plane(κ ab ) and along c-axis (κ c ) is 7.6 order at 300 K, while as at 673 K, this value about 5.6. The thermoelectric figure of merit ZT along c-axis (0.15) is higher than that (0.1) along the ab-plane, according to the ultralower out-of-plane thermal conductivity. The electronic band structure results, which were examined by angle-resolved photoemission spectroscopy (ARPES) predicted the potential of improving thermoelectric performance of SnSe 2 single crystal by electron doping.

Two-Dimensional Mechano-thermoelectric Heterojunctions for Self-Powered Strain Sensors

“…We demonstrate the feasibility of the self-powered strain sensing approach by first establishing the development of a Seebeck voltage under a temperature gradient (Figure b). The sign and magnitude of the Seebeck coefficient, that is, the slope in the temperature–Seebeck voltage plot, agree with the values of p-type CVD graphene and are much smaller than SnSe 2 , furthermore confirming the importance of graphene to the thermoelectric performance.…”

“…The synergistic contribution of graphene and SnSe 2 to this effect can be identified from the thickness dependence of ZT (Figure f). At high SnSe 2 thickness, a lower contribution of graphene conductance and a longer carrier path result in a decreased ZT which asymptotically tends to the reported value for high-quality bulk SnSe 2 …”

“…At high SnSe 2 thickness, a lower contribution of graphene conductance and a longer carrier path result in a decreased ZT which asymptotically tends to the reported value for high-quality bulk SnSe 2 . 28 The formation of SnSe 2 /graphene heterojunctions not only enhances the thermoelectric performance but also imparts the structure with unprecedented strain sensing capabilities. Tensile deformation was accomplished through bending of the plastic/SnSe 2 /graphene structure (inset Figure 4a) and variable deformation was related to the strain experienced at the SnSe 2 /graphene interface.…”

Br-Doped n-Type SnSe2: Single-Crystal Growth and Thermoelectric Properties

“…The calculated lattice constants of the samples are about a = 3.810 ± 0.005 Å and c = 6.119 ± 0.011 Å, which coincide with the previous reports. 15,28,29 The mass density of the samples, obtained using the Archimedes principle, is 5.92 ± 0.06 g cm −3 , which is comparable to the theoretical value of 5.95 g cm −3 . 30 To explore the effects of Br doping on the charge carriers in the SnSe 2 single crystals, we determined the temperaturedependent carrier concentration from 300 to 673 K for all samples.…”

Controlled Morphology and Its Effects on the Thermoelectric Properties of SnSe2 Thin Films

“…Thus, the increase in overall power factor of the M4 sample was the result of the synergistic effect of morphology on the σ and S, where we obtained prominent enhancement in σ without largely compromising the S values [22][23][24]. The observed PF values in this work are in the range of the previously reported literature for the SnSe 2 structures [25,26]. The overall study suggests that as the reaction time increased, the phase purity was enhanced for the SnSe 2 structure and led to higher σ and PF.…”