The development of reliable and cost-effective thermoelectric devices depends not only on the identification of suitable materials, but also on the associated fabrication processes. Gen- eral microstructural features, such as porosity and grain size, affect transport of heat and electrical current. As noted above, the properties of ZnO vary significantly with grain size. In addition to these general features, the properties of layered struc- tures are anisotropic, so orientation affects performance.