Thermoelectric Characterization Platform for Electrochemically Deposited Materials

Abstract

Successful optimization of the thermoelectric (TE) performance of materials, described by the figure of merit zT, is a key enabler for its application in energy harvesting or Peltier cooling devices. While the zT value of bulk materials is accessible by a variety of commercial measurement setups, precise determination of the zT value for thin and thick films remains a great challenge. This is particularly relevant for films synthesized by electrochemical deposition, where the TE material is deposited onto an electrically conductive seed layer causing an in-plane short circuit. Therefore, a platform for full in-plane zT characterization of electrochemically deposited TE materials is developed, eliminating the impact of the electrically conducting seed layer. The characterization is done using a suspended TE material within a transport device which was prepared by photolithography in combination with chemical etching steps. An analytical model to determine the thermal conductivity is developed and the results verified using finite element simulations. Taken together, the full in-plane zT characterization provides an inevitable milestone for material optimization under realistic conditions in TE devices. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim