Electrical characterization and conduction mechanism of impurity-doped BaSi2 films grown on Si(111) by molecular beam epitaxy

The carrier concentrations and mobilities of impurity (Sb, In, Ga, Al, Ag, and Cu)-doped BaSi2 films grown by molecular beam epitaxy on highly resistive n-or p-Si(111) substrates were measured at room temperature using the van der Pauw technique. Sb-, Ga- and Cu-doped BaSi2 exhibited n-type conductivity, while InAl- and Ag-doped BaSi2 exhibited p-type conductivity. The temperature dependence of resistivity indicated that the carrier transport in Ga-, Al-, Ag-, and Cu-doped BaSi2 is well explained by both Shklovskii-Efros-type and Mott-type variable range hopping conduction. (C) 2012 Elsevier B. V. All rights reserved.