Temperature dependent transport study of the SiOx/Ge/SiOx system

The transport properties of the SiO_x/Ge/SiO_x system are studied using the van der Pauw technique as function of temperature in the range from 35 K to 150 K for two representative samples grown by Radio Frequency sputtering under different conditions. It is found that variable range hopping conduction explains the temperature dependence of the resistivity. For both samples, the nearest neighbor hopping conduction process explains the temperature dependence of the resistivity in the range between 66 K and 150 K. For the sample with the roughest surface, Efros-Shkovskiis variable range hopping process explains better the results below 66 K, while for the other one, a combination of Motts variable range hopping in two and three dimensions explain better the results in the same temperature range.