The Effect of the MEMS Measurement Platform Design on the Seebeck Coefficient Measurement of a Single Nanowire

Abstract

In order to study the thermoelectric properties of individual nanowires, a thermoelectric nanowire characterization platform (TNCP) has been previously developed and used in our chair. Here, we report on a redesigned platform aiming to optimize performance, mechanical stability and usability. We compare both platforms for electrical conductivity and the Seebeck coefficient for an individual Ag nanowire of the previously-used batch and for comparable measurement conditions. By this, the measurement performance of both designs can be investigated. As a result, whereas the electrical conductivity is comparable, the Seebeck coefficient shows a 50% deviation with respect to the previous studies. We discuss the possible effects of the platform design on the thermoelectric measurements. One reason for the deviation of the Seebeck coefficient is the design of the platform leading to temperature gradients along the bond pads. We further analyze the effect of bonding materials Au and Pt, as well as the effect of temperature distributions along the bond pads used for the thermovoltage acquisition. Another major reason for the variation of the measurement results is the non-homogeneous temperature distribution along the thermometer. We conclude that for the measurement of small Seebeck coefficients, an isothermal positioning of voltage-probing bond pads, as well as a constant temperature profile at the measurement zone are essential.

Robust, Flexible Thermoelectric Film for Energy Harvesting by a Simple and Eco-Friendly Method

“…Other samples in Figure 2a showed negative S, indicating n-type conduction. The absolute S of the Ag 3 Te film is lower than that of the Ag 2 Te film because of containing too much Ag phase which has a low S. 35 The S of Ag 0.5 Te decreased from 404.4 μV K −1 at RT to 329.4 μV K −1 at 430 K, whereas the absolute S values of Ag 2 Te and Ag 3 Te increased monotonously (from 48.3 and 28.0 μV K −1 at RT to 77.4 and 40.7 μV K −1 at 430 K, respectively). It can be seen that upon increasing the value of Ag/Te, the σ value increases significantly.…”

Semimetal to semiconductor transition in Bi/TiO2 core/shell nanowires

“…All processes were performed in a high vacuum environment to prevent the formation of an oxidation layer between the core and the shell material. A thermoelectric nanowire characterization platform (TNCP) 13,14 was used to perform a full analysis of the transport properties of individual Bi-based core/shell nanowires. An electron transparent gap (width: 10 mm to 20 mm) serves as thermal insulation of the suspended nanowire and enables an investigation of the specimen by scanning (SEM) and transmission electron microscopy (TEM).…”

Imaging Thermoelectric Properties at the Nanoscale

“…The existing methods can be separated into two categories: on the one hand, methods measuring single isolated nanowires (NWs) and, on the other hand, methods measuring NWs embedded in a matrix which constitutes the actual thermoelectric device. Concerning single isolated NWs, microchip suspended structures or platforms are powerful techniques through their capacity to measure several properties of a wide variety of NWs over a wide temperature range [ 17 , 18 , 19 , 20 ]. However, these methods are difficult to implement and the necessity to isolate the individual nanowire, the estimation of the contact resistances and the possible oxidation of the nanowire are other major drawbacks.…”