Theoretical Insights into the Growth of Direct Bandgap III-V Semiconductors on Diverse Substrates

III-V semiconductors such as GaN, GaP, and InN, are critical materials for next-generation electronic and optoelectronic devices. Their direct bandgaps, superior carrier mobilities and efficient photon-to-electron conversion offer significant advantages over indirect-bandgap silicon. Despite their exceptional properties and versatile applications, achieving reliable and low-defect integration of these materials with existing silicon-based technologies remains a challenge. Here, we combine first-principles density functional theory (DFT) and tailored ReaxFF reactive force fields methods to investigate the growth mechanisms and resulting polarity of III-V compounds on diverse substrates, such as crystalline Si and Si₃N₄, and 2D transition metal dichalcogenides (TMDs), alongside various amorphous surface stated created via nitridation or oxidation. This multi-scale approach investigations defines key kinetic and thermodynamic factors governing interface and sample quality, offering useful atomistic insights for rationalizing synthesis strategies via molecular beam epitaxy (MBE) and chemical vapor deposition (CVD).