A method of fabricating a CoSb.sub.3-based thermoelectric device is disclosed. The method includes providing a high-temperature electrode, providing a buffer layer on the high-temperature electrode, forming composite n-type and p-type layers, attaching the buffer layer to the composite n-type and p-type layers, providing a low-temperature electrode on the composite n-type and p-type layers and separating the composite n-type and p-type layers from each other to define n-type and p-type legs between the high-temperature electrode and the low-temperature electrode.