【Others Papers】Band Offset and Defect Properties of Ultra-Wide Bandgap Semiconductor Ga₂O₃ and Its Alloys: From First Principles to Device Modelling

      Researchers from the Queen's University Belfast have published a dissertation titled "(Invited) Band Offset and Defect Properties of Ultra-Wide Bandgap Semiconductor Ga₂O₃ and Its Alloys: From First Principles to Device Modelling " in ECS Meeting Abstracts.

Abstract

      The electronic properties of ultra-wide band gap semiconductors, notably β-Ga₂O₃, have been intensively investigated for applications such as high-power electronics and solar-blind photodetectors. Until recently, atomistic modelling has been mostly focused on pure β-Ga₂O₃, e.g., to determine its band offset and dopability. Despite this effort, mechanisms for effective p-type doping of pure β-Ga₂O₃ remain elusive. Alloying β-Ga₂O₃ with Al₂O₃ or In₂O₃ provides an alternative and promising strategy for tuning mechanical and electronic properties, including lattice mismatch, band offsets in heterostructure and defect formation energies. To this end, atomistic modelling from first principles offers valuable insights that complement experimental measurements using, e.g., capacitance–voltage (C-V) characterisation or X-ray Photoelectron Spectroscopy (XPS).

      In the first part of this talk, first principles modelling using density functional theory (DFT) is briefly reviewed along with the main results for pure β-Ga₂O₃. In the second part, recent investigations of Ga₂O₃-based alloys are presented [3]. These investigations include the assessment of the critical thickness for epitaxially grown in the (100B), (010), (001B), and (-201) directions and the formation energies of substitutional donors (Si, Sn, C, Ge, Ta, Zr, Hf) and acceptors (Mg, Zn, Cu). Accurate band offsets from first principles calculations are also combined with Technology Computer-Aided Design (TCAD) modelling, showing good agreement with experimental results in. Our findings underscore the importance of growth orientation, strain, and substitutional impurities investigation for Ga₂O₃-based alloys for precise control of band offset and defect formation.

DOI：

https://doi.org/10.1149/MA2025-02331664mtgabs