Investigating Stable Low-Energy Gallium Oxide (Ga₂O₃) Polytypes: Insights into Electronic and Optical Properties from First Principles

Abstract

This study provides a comprehensive analysis of the electronic and optical properties of low-energy gallium oxide (Ga 2 O 3 ) polytypes not considered earlier. Among these polytypes, the monoclinic structure (β-Ga 2 O 3 ) holds significant relevance for both research and practical applications due to its superior stability under typical conditions. The primary aim of this research is to identify new and stable Ga 2 O 3 polytypes that may exist under zerotemperature and zero-pressure conditions. To achieve this objective, we employ the VASP code to investigate electrical and optical properties, as well as stability assessments. Additionally, we examine phonon and thermal properties, including heat capacity, for all polytypes. This study also encompasses the computation of full elastic tensors and elastic moduli for all polytypes at 0 K, with Poisson's and Pugh's ratios confirming their ductile nature. Furthermore, we present the first ever report on the Raman-and infrared (IR)-active modes of these stable Ga 2 O 3 polytypes. Our findings reveal that these mechanically and dynamically stable Ga 2 O 3 polytypes exhibit semiconductive properties, as evidenced by electronic band structure investigations. This research offers valuable insights into the optical characteristics of Ga 2 O 3 polytypes with potential applications spanning various fields.

Blue light emission enhancement and robust pressure resistance of gallium oxide nanocrystals

“…The volume data was fitted with a third-order Birch–Murnaghan equation of state: 31–33 where V 0 is the volume at zero pressure, B 0 is the bulk modulus at ambient pressure, and is a parameter for the pressure derivative. The fitting of the Birch–Murnaghan equation indicated that the isothermal bulk modulus B 0 for the Ga 2 O 3 NCs was estimated as 137.34 GPa, much higher than that (85.9 GPa) of the bulk counterpart 34 (Fig. S9†).…”