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Direct determination of band-gap renormalization in degenerately doped ultrawide band gap β-Ga2O3 semiconductor

DOI: 10.1103/PhysRevB.106.205305 DOI Help

Authors: Jiaye Zhang (Xiamen University; Southern University of Science and Technology) , Joe Willis (University College London; Diamond Light Source) , Zhenni Yang (Xiamen University) , Ziqian Sheng (Xiamen University) , Lai-Sen Wang (Xiamen University) , Tien-Lin Lee (Diamond Light Source) , Lang Chen (Southern University of Science and Technology) , David O. Scanlon (University College London) , Kelvin H. L. Zhang (Xiamen University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 106

State: Published (Approved)
Published: November 2022
Diamond Proposal Number(s): 24219 , 31069

Abstract: Ga 2 O 3 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 c m − 3 to 2.6 × 10 20 c m − 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 3 s 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.

Journal Keywords: Density of states; Electrical conductivity; Electronic structure; Doped semiconductors; Thin films; Wide band gap systems; Density functional theory; Epitaxy; Hard x-ray photoelectron spectroscopy; Laser ablation; Physical deposition

Diamond Keywords: Semiconductors

Subject Areas: Physics, Materials


Instruments: I09-Surface and Interface Structural Analysis

Added On: 24/11/2022 09:13

Discipline Tags:

Surfaces Physics Hard condensed matter - structures Electronics Materials Science interfaces and thin films

Technical Tags:

Spectroscopy X-ray Photoelectron Spectroscopy (XPS) Hard X-ray Photoelectron Spectroscopy (HAXPES)