Room temperature transport measurements on Bridgman-grown p-type CuIn1−xGaxSe2

Room temperature measurements were made of electrical conductivity (σ), Hall coefficient (RH) and Seebeck coefficient (α) on filamentary samples of p-type CuInSe2 and CuIn1−xGaxSe2 with x⩽0.3, cut from vertically grown Bridgman ingots. Analysis of the results was done on a two-carrier basis, due to the higher ratio of electron to hole mobility (b) in these materials compared to elemental semiconductors. This treatment yielded a preferred b-value of 5 and to lower calculated hole concentrations than (RHe)−1 and higher hole mobilities than RHσ, based on a one-carrier interpretation. This effect was particularly marked in p-type samples with a hole concentration below 1017 cm−3, where even a few percent of minority electrons can play an important role.