学術雑誌論文 Measurement of valence-band offset at native oxide/BaSi2 interfaces by hard x-ray photoelectron spectroscopy

Takabe, Ryota  ,  Du, Weijie  ,  Ito, Keita  ,  Takeuchi, Hiroki  ,  Toko, Kaoru  ,  Ueda, Shigenori  ,  Kimura, Akio  ,  Suemasu, Takashi

119 ( 2 )  , p.025306 , 2016-01 , American Institute of Physics
ISSN:0021-8979
NII書誌ID(NCID):AA00693547
内容記述
Undoped n-type BaSi2 films were grown on Si(111) by molecular beam epitaxy, and the valence band (VB) offset at the interface between the BaSi2 and its native oxide was measured by hard x-ray photoelectron spectroscopy (HAXPES) at room temperature. HAXPES enabled us to investigate the electronic states of the buried BaSi2 layer non-destructively thanks to its large analysis depth. We performed the depth-analysis by varying the take-off angle (TOA) of photoelectrons as 15°, 30°, and 90° with respect to the sample surface and succeeded to obtain the VB spectra of the BaSi2 and the native oxide separately. The VB maximum was located at −1.0 eV from the Fermi energy for the BaSi2 and −4.9 eV for the native oxide. We found that the band bending did not occur near the native oxide/BaSi2interface. This result was clarified by the fact that the core-level emission peaks did not shift regardless of TOA (i.e., analysis depth). Thus, the barrier height of the native oxide for the minority-carriers in the undoped n-BaSi2 (holes) was determined to be 3.9 eV. No band bending in the BaSi2 close to the interface also suggests that the large minority-carrier lifetime in undoped n-BaSi2 films capped with native oxide is attributed not to the band bending in the BaSi2, which pushes away photogenerated minority carriers from the defective surface region, but to the decrease of defective states by the native oxide.
本文を読む

https://tsukuba.repo.nii.ac.jp/?action=repository_action_common_download&item_id=36626&item_no=1&attribute_id=17&file_no=1

このアイテムのアクセス数:  回

その他の情報