The Fabrication of Fe-Doped TiCoSb Thin Films by Magnetron Sputtering and Rapid Thermal Annealing

Abstract

TiCoSb-based half-Heusler compounds, which are narrow band gap semiconductors with a high Seebeck coefficient, have been intensively studied in bulk form but rarely in thin films. In this article TiFexCo1-xSb (x=0, 0.17) thin films were synthesized on n-type single crystal Si (100) and MgO (100) substrates by DC magnetron sputtering followed by rapid thermal annealing. The X-ray diffraction patterns show that Fe doping does not affect the crystallization temperature of TiCoSb phase, but seem to induce the formation of binary phases like TiSb. Hall measurements reveal that the undoped TiCoSb thin films are n-type semiconducting, while TiFe0.2Co0.8Sb turns to p-type with half-order higher carrier concentration of 1.5×1021 cm-3. The vibrating sample magnetometer spectrum indicate that the TiCoSb thin film is non-magnetic and TiFexCo1-xSb (x=0.17) is weak magnetic.