Growth of the Bi2Se3 Surface Oxide for Metal–Semiconductor–Metal Device Applications
2016
Yeh, Yun-Chieh | Ho, Po-Hsun | Wen, Cheng-Yen | Shu, Guo-Jiun | Sankar, Raman | Chou, Fang-Cheng | Chen, Chun-Wei
The effect of the surface structure of Bi₂Se₃ on its interior properties has been well studied recently, but the interfacial structure and electrical properties of the oxidized Bi₂Se₃ surface are little known. In contrast to the self-limited formation of native oxide on Bi₂Se₃, the degree of oxidation on the Bi₂Se₃ surface in oxygen plasma is enhanced. Results of transmission electron microscopy and X-ray photoelectron spectroscopy show that the surface of the oxidized Bi₂Se₃ is composed of a layer of amorphous bismuth oxide (BiOₓ), and the thickness of the BiOₓ layer can be controlled by the length of the plasma process. Electrical measurements of this structure present the Schottky-type transport property at the interface between the oxidized layer and the bulk Bi₂Se₃ crystal, and the turn-on voltage depends on the thickness of the surface BiOₓ layer. This study of the structure, formation mechanism, and electrical properties of the surface oxide of Bi₂Se₃ formed in oxygen plasma provides useful information for future development of electronic devices based on bismuth chalcogenides.
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