Large bandgap tuning in corundum Al2(O1−xSex)3

Liu, Xiaoli; Ober, Seamus; Tang, W.H.; Tan, Chee-Keong

doi:10.1039/d1tc00907a

Cited by 3 publications

References 56 publications

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Natural band alignment of MgO1−xSx alloys

et al. 2023

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We have calculated formation enthalpies, bandgaps, and natural band alignment for MgO1−xSx alloys by first-principles calculation based on density functional theory. The calculated formation enthalpies show that the MgO1−xSx alloys exhibit a large miscibility gap, and a metastable region was found to occur when the S content was below 18% or over 87%. The effect of S incorporation for bandgaps of MgO1−xSx alloys shows a large bowing parameter (b ≃ 13 eV) induced. The dependence of the band lineup of MgO1−xSx alloys on the S content by using two different methods and the change in the energy position of the valence band maximum (VBM) were larger than those of the conduction band minimum. Based on the calculated VBM positions, we predicted that MgO1−xSx with S content of 10%–18% can be surface charge transfer doped by high electron affinity materials. This work provides an example to design for p-type oxysulfide materials.

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Natural band alignment of MgO1−xSx alloys

et al. 2023

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Electronic properties and formation energy of chalcogen-doped (S/Se/Te) corundum Al2O3

Liao,

Song,

Xie

et al. 2024

Journal of Applied Physics

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α-Al2O3 is renowned for its extensive bandgap and diverse applications in electronic and optoelectronic devices. Employing density-functional theory-based methods, this study investigates the feasibility of chalcogen doping (S, Se, Te) in α-Al2O3. Standard modeling tools are utilized to construct α-Al2O3 supercells, focusing on the calculations of individual chalcogen-related and native point defects resulting from single-atom doping. Our analysis systematically explores the formation energies and transition levels associated with chalcogen (S, Se, Te) doping in oxygen (or aluminum) sites in Al-rich (or O-rich) limits. We observe a trend where increasing atomic number (from S to Te) correlates with a higher difficulty in forming anion-doped α-Al2O3, but a lower barrier to cationic doping. The results indicate a preferential substitution of chalcogen atoms for aluminum in O-rich environments. Specifically, in varying oxygen conditions, the dominant defect types, their prevalence, and defect formation energies in α-Al2O3 are significantly altered following chalcogen doping, offering new insights into defect processes in α-Al2O3.

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