Investigation of some electrical properties of silicon boride

Electric properties of boron alloys with silicon differing from SiB14 by the composition to the side of decreasing boron content in a wide range of temperatures (from 100 to 1500 K) are investigated. Electric conductivity (σ) measurements have shown that it weakly depends on temperature in the 300-700 K range and rises according to the exponential law due to the mobility increase of current carriers in the 700-1500 deg and 100-250 deg ranges. Thermo- e.m.f.(α) increases in the range of 700-1500 K with the curve bend being 110 μV/deg and then decreases when the temperature rises. Supposing that thermo-e.m.f. decrease is conditioned by proper conductivity, the thermal width of the forbidden zone is estimated. It is noted that the nature of temperature dependences σ and α of the material considered (Si9) differs from the nature of these dependences for SiB14; for the latter, up to T=1300 K the range of proper conductivity is not observed which proves a significant difference in the values of the forbidden zone of these materials