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 CuInSe
₂
and CuIn
_1-x
Ga
_x
Se
₂
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
_H
e)
^-1
and higher hole mobilities than R
_H
sigma, based on a one-carrier interpretation. This effect was particularly marked in p-type samples with a hole concentration below 10
¹⁷
cm
^-3
, where even a few percent of minority electrons can play an important role