Spatially controlling the Fermi level of topological insulators and keeping its electronic states stable are indispensable processes to put this material into practical use for semiconductor spintronics devices. So far, however, such a method has not been established yet. Here we show a novel method for doping hole into n-type topological insulators Bi2X3 (X= Se, Te) that overcomes the shortcomings of the previous reported methods. The key of this doping is to adsorb H2O on Bi2X3 decorated with a small amount of carbon, and its trigger is the irradiation of photon with sufficient energy to excite core-electrons of the outermost layer atoms. This method allows controlling the doping amount by the irradiation time, and acts as photolithography. Such a tunable doping makes it possible to design the electronic states at the nanometer scale, and thus paves a promising avenue toward the realization of novel spintronics devices based on topological insulators.
@article{arxiv.2503.20334,
title = {Spatial Control of Charge Doping in n-Type Topological Insulators},
author = {Kazuyuki Sakamoto and Hirotaka Ishikawa and Takashi Wake and Chie Ishimoto and Jun Fujii and Hendrik Bentmann and Minoru Ohtaka and Kenta Kuroda and Natsu Inoue and Takuma Hattori and Toshio Miyamachi and Fumio Komori and Isamu Yamamoto and Cheng Fan and Peter Krüger and Hiroshi Ota and Fumihiko Matsui and Friedrich Reinert and José Avila and Maria C. Asensio},
journal= {arXiv preprint arXiv:2503.20334},
year = {2025}
}