The electronic properties of p- and n-type Ba8Ga16Ge30 (BGG) are studied using soft X-ray photoelectron spectroscopy at a high-energy facility. Three bands are resolved in the valence band region. The first band for n-type BGG is sensitive to temperature, while the second band is sensitive for p- type BGG. The change in the ratio of Ba to Ga, from which the carrier type is controlled in this system, modifies the positions of Ga residing at the larger (Ga-CGe)(24) cage. This modi. cation in the host network is responsible for the large differences observed in electronic properties of p- and n-BGGs in this clathrate family. (C) 2009 Elsevier B. V. All rights reserved.