Electron-to-Hole Mobility Ratio in P-Type Bridgman-Grown CuInSe2 from Room Temperature Transport Measurements

Room temperature measurements were made of electrical conductivity (sigma), Hall coefficient (R_H) and Seebeck coefficient (alpha) on filamentary samples of p-type CuInSe₂ and CuIn _1-xGa_xSe₂ with xles0.3, 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 (R_He)^-1 and higher hole mobilities than R_Hsigma, 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