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β-Ga2O3 has been subjected to intense research interest as an ultrawide bandgap semiconductor. The epitaxial growth technique of β-Ga2O3 thin films plays a fundamental and vital role in Ga2O3-based device fabrication. In this work, the epitaxial growth mechanisms of β-Ga2O3 on four low-Miller-index facets, (100), (010), (001), and ( 2 ¯ 01), are systematically explored using large-scale machine-learning molecular dynamics simulations at the atomic scale. The simulations reveal that the migration of the face-centered cubic stacking O sublattice plays a dominant role in the different growth mechanisms between the (100)/(010)/(001) and ( 2 ¯ 01) orientations. The resultant complex combinations of the stacking faults and twin boundaries are carefully identified and show good agreement with experimental observations and ab initio calculations. Our results provide useful insights into the gas-phase epitaxial growth of β-Ga2O3 thin films and suggest possible ways to tailor its properties for specific applications. [ABSTRACT FROM AUTHOR]

In this work, we focused on investigating the transport-limited trapping effects in GaN-on-Si buffer layers as well as impact of the thickness of buffer layers (TBuf) upon such effects. Vertical transport dynamics of charges within the buffer layers and their key energy levels are quantitatively and statistically investigated and analyzed. The results show that an increased TBuf diminishes both impurity conduction of the defect band formed by carbon doping as well as the injection of electrons from the substrate, greatly diminishing the current collapse and improving the stability of the device. Such enhancement is mainly attributed to the reduced vertical electric field within the thickened epitaxy, which provides an additional pathway to address the current collapse and yields more efficient power GaN-on-Si devices. [ABSTRACT FROM AUTHOR]