Competing conduction mechanisms of two-dimensional electrons and bulk-like electrons in the n-type surface of the naturally oxidized p-type HgCdTe thin film

The surface transport properties of naturally oxidized p-type Hg0.776Cd0.224Te thin film were investigated in the magnetic-field region 0–14 T and in the temperature region 8–300 K. The Hall electron concentration increases with temperature, while the surface concentration of the two-dimensional electrons in the naturally oxidized surface, calculated by Shubnikov–de Haas oscillations, decreases as temperature increases at temperatures below 20 K. The contradiction and the extraordinary quantum Hall filling factors are accounted for by assuming extra bulk-like electrons in the surface region, which dominate the surface transport properties at temperatures over 8 K.