Enhancing the mechanical strength of β-Ga2O3 with Al alloying

$\ensuremath{\beta}$-${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ is a promising ultrawide-bandgap semiconductor material for power electronics and optical applications. However, its low hardness and cleavage nature pose major challenges to crystal growth and processing. In this study, $\mathrm{Al}$ alloying is proposed as an effective method to improve the mechanical properties of $\ensuremath{\beta}$-${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ as seed crystals and substrates. First-principle calculations are employed to assess the alloying-induced evolution of crystal structure and mechanical behavior. Elastic constants, ideal shear strengths, and ideal cleavage strengths are all shown to enhance with increasing $\mathrm{Al}$ concentration. Our analysis reveals the possibility of obtaining the mechanically favorable $\ensuremath{\beta}$-${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ seed crystals and substrates with proper $\mathrm{Al}$ alloying, providing theoretical guidance to the development of $\ensuremath{\beta}$-${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ materials and devices.