Fabrication and characterization of nickel contacts for magnesium silicide based thermoelectric generators

Magnesium silicide based solid solutions are highly attractive materials for thermoelectric energy harvesting due to their abundance and excellent thermoelectric properties. Identification and testing of suitable contacts is - besides material optimization - the major challenge in the development of thermoelectric modules. We have applied Ni contacts on doped Mg2Si samples using a simple one-step sintering technique. These contacts were analyzed by combining microstructural analysis with spatially resolved and temperature dependent contact resistance measurements. We observe very good adhesion, homogeneous and low contact resistances < 10 mu Omega cm(2). as well as good stability with temperature. Three different approaches for determining the contact resistances are compared and the respective errors are discussed. (C) 2015 The Authors. Published by Elsevier B.V.