Deposition of thermoelectric strontium hexaboride thin films by a low pressure CVD method

Thin films of SrB6 were deposited on sapphire substrates using a chemical vapor deposition method, with elemental strontium and decaborane, B10H14, used as the strontium and boron sources, respectively. The formation of highly crystalline, phase-pure SrB6 films was confirmed with X-ray diffraction and reflection high energy diffraction (RHEED) analysis, and the films' thermoelectric transport properties were measured. A relatively high deposition temperature of 850-950 °C was found to be optimal for obtaining well-crystallized films at an extremely high deposition rate. The thermoelectric transport properties of the SrB6 thin films were observed to be comparable to those reported for bulk materials, but an unexpectedly high electrical resistivity led to a reduced power factor value for the thin films.