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Direct determination of band-gap renormalization in degenerately doped ultrawide band gap β-Ga_{2}O_{3} semiconductor

Zhang, Jiaye; Willis, Joe; Yang, Zhenni; Sheng, Ziqian; Wang, Lai-Sen; Lee, Tien-Lin; Chen, Lang; ... Zhang, Kelvin HL; + view all (2022) Direct determination of band-gap renormalization in degenerately doped ultrawide band gap β-Ga_{2}O_{3} semiconductor. Physical Review B , 106 (20) , Article 205305. 10.1103/physrevb.106.205305. Green open access

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Abstract

Ga2O3 is emerging as a promising wide band-gap semiconductor for high-power electronics and deep ultraviolet optoelectronics. It is highly desirable to dope it with controllable carrier concentrations for different device applications. This work reports a combined photoemission spectroscopy and theoretical calculation study on the electronic structure of Si doped Ga_{2}O_{3} films with carrier concentration varying from 4.6×10^{18} cm^{−3} to 2.6×10^{20} cm^{−3}. Hard x-ray photoelectron spectroscopy was used to directly measure the widening of the band gap as a result of occupation of conduction band and band-gap renormalization associated with many-body interactions. A large band-gap renormalization of 0.3 eV was directly observed in heavily doped Ga_{2}O_{3}. Supplemented with hybrid density functional theory calculations, we demonstrated that the band-gap renormalization results from the decrease in energy of the conduction band edge driven by the mutual electrostatic interaction between added electrons. Moreover, our work reveals that Si is a superior dopant over Ge and Sn, because Si 3s forms a resonant donor state above the conduction band minimum, leaving the host conduction band mostly unperturbed and a high mobility is maintained though the doping level is high. Insights of the present work have significant implications in doping optimization of Ga_{2}O_{3} and realization of optoelectronic devices.

Type: Article
Title: Direct determination of band-gap renormalization in degenerately doped ultrawide band gap β-Ga_{2}O_{3} semiconductor
Open access status: An open access version is available from UCL Discovery
DOI: 10.1103/physrevb.106.205305
Publisher version: https://doi.org/10.1103/PhysRevB.106.205305
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions.
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry
URI: https://discovery.ucl.ac.uk/id/eprint/10161184
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