Electrical and magnetic properties of Mn-doped Si thin films

Abstract We have studied electrical and magnetic properties of x  at% Mn-doped Si thin films with high Mn concentrations ( x  at%=7.5, 9.1, and 11.3), which were prepared by molecular beam epitaxy. Our data reveals that the films are p-type semiconductors at room temperature, and their hole density is about 10 20  cm −3 . When temperature increases from 5 to 300 K, the resistivity of 7.5 at% Mn film decreases and can be described by Mott's variable-range-hopping model. The resistivity of 9.1 at% Mn film does not change remarkably. In contrast, the resistivity of 11.3 at% Mn film increases, indicating metallic characteristics at temperatures below 240 K. Magnetic measurements reveal that the films exhibit the low-temperature ferromagnetic ordering, which is largely related to the presence of secondary phase.