Hard X-ray photoemission study of bulk single-crystalline InGaZnO

芝田 悟朗 ; 他9名*

Shibata, Goro; 9 of others*

We performed hard X-ray photoemission spectroscopy (HAXPES) experiments of bulk single-crystalline InGaZnO (sc-IGZO), which was recently synthesized via the optical floating zone method, in order to reveal the bulk intrinsic electronic structure. We find that oxygen vacancies are preferentially located around In atoms in as-grown crystals, which are filled out by post-annealing in an oxygen atmosphere. The subgap states near the valence-band maximum (VBM) were much weaker than those in the previous study even without oxygen annealing, which suggests that the loss of crystallinity is relevant to the formation of them in addition to the oxygen vacancies.