Hidden Direct Bandgap of Bi 2 O 2 Se by Se Vacancy and Enhanced Direct Bandgap of Bismuth Oxide Overlayer

The Bi O Se surfaces are well-known to possess 50% Se vacancies, yet they have shown no in-gap states within the indirect bandgap (∼0.8 eV). We have found that the hidden in-gap states arising from the Se vacancies in a 2 × 1 pattern induce a reduced direct bandgap (∼0.5 eV). Such a reduced direct b...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2024-02, Vol.15 (6), p.1590-1595
Main Authors: Han, Sang Wook, Yun, Won Seok, Seong, Seungho, Tahir, Zeeshan, Kim, Yong Soo, Ko, Minji, Ryu, Sunmin, Bae, Jong-Seong, Ahn, Chang Won, Kang, Jeongsoo
Format: Article
Language:English
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Summary:The Bi O Se surfaces are well-known to possess 50% Se vacancies, yet they have shown no in-gap states within the indirect bandgap (∼0.8 eV). We have found that the hidden in-gap states arising from the Se vacancies in a 2 × 1 pattern induce a reduced direct bandgap (∼0.5 eV). Such a reduced direct bandgap is responsible for the high electron mobility of Bi O Se. Moreover, the Bi oxide overlayers of the Bi thin films, formed through air exposure and annealing, unexpectedly exhibit a large direct bandgap (∼2.1 eV). The simplified fabrication of Bi oxide overlayers provides promise for improving Bi O Se electronic devices and enhancing photocatalytic activity.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.3c03223