Abstract
Tin selenide (SnSe) has been the subject of great attention in the last years due to its highly efficient thermoelectricity and its possibilities as a green material, free of Pb and Te. Here, we report for the first time a thermoelectricity and transport study of individual SnSe micro- and nano-wires with diameters in the range between 130 nm and 1.15 μm. X-ray diffraction and transmission electron microscopy analyses confirm an orthorhombic SnSe structure with Pnma (62) symmetry group and 1:1 Sn:Se atomic ratio. Electrical and thermal conductivity and the Seebeck coefficient were measured in each individual nanowire using a specialized suspended microdevice in the 150–370 K temperature range, yielding a thermal conductivity of 0.55 Wm−1 K−1 at room temperature and ZT ~ 0.156 at 370 K for the 130 nm diameter nanowire. The measured properties were correlated with electronic information obtained by model simulations and with phonon scattering analysis. The results confirm these structures as promising building blocks to develop efficient temperature sensors, refrigerators and thermoelectric energy converters. The thermoelectric response of the nanowires is compared with recent reports on crystalline, polycrystalline and layered bulk structures.
Highlights
Due to the increasing use and costs of fossil fuels and to the contamination that conventional energy production is causing, a worldwide effort is underway to find alternative sources of energy that can replace traditional ones
The furnace was heated to 860 °C and 550 °C in the precursor and substrate zone respectively, at a rate of 10 °C min−1 and the temperature was maintained constant for 60 min, before natural cooling to room temperature
We have reported the VLS synthesis of SnSe nanowires and successfully measured the Seebeck coefficient and the thermal and electrical conductivities of individual nanowires with diameters from ~130 nm to ~1.15 μm, over a 150–370 K temperature range
Summary
Due to the increasing use and costs of fossil fuels and to the contamination that conventional energy production is causing, a worldwide effort is underway to find alternative sources of energy that can replace traditional ones. It was suggested that this interdependence can be bypassed using low-dimensional structures such as quantum dots and nanowires, where phonon-boundary scattering reduces κ without changing the properties of the material at the scale of the electron’s scattering events; at the same time the asymmetric density of states near the Fermi level in nanostructures can increase S8–11. Following this idea, a ZT = 2 at room temperature was reported in 2002 for a quantum-dot superlattices[12]. Calculations suggest the possibility of a high thermoelectric figure of merit in nanostructured SnSe crystals[32], yet neither individual nanostructures or the diameter dependence of thermoelectric performance in SnSe nanowires has been reported
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
