Heteroepitaxial growth of β-Ga2O3 thin films on Si (111) substrates via interfacial engineering for self-powered ultraviolet photodetectors

• AlN buffer layer enables heteroepitaxial growth of β -Ga 2 O 3 thin films on Si (1 1 1). • Optimized PLD parameters achieve high-phase-purity and low-defect β -Ga 2 O 3 films. • Strong Ga-O bonding and near-stoichiometry enhance optical quality of β -Ga 2 O 3 films. • β -Ga 2 O 3 films exhibit sharp UV cutoff (∼270 nm) and high solar-blind selectivity. • Self-powered solar-blind photodetector fabricated on CMOS-compatible Si platform. β -Ga 2 O 3 holds great promises for solar-blind ultraviolet photodetection and energy-efficient electronic electronics. Overcoming the lattice and thermal mismatch in heteroepitaxial growth on Si is critical to achieving complementary metal–oxide–semiconductor (CMOS)-compatible and cost-effective devices. In this work, we demonstrate the AlN-mediated heteroepitaxial growth of β -Ga 2 O 3 thin films on Si (1 1 1) substrate via pulsed laser deposition. We systematically investigate the influence of key growth parameters, specifically temperature and oxygen pressure, on the film crystallinity, demonstrating that optimized conditions effectively reduce defects and improve phase purity. Comprehensive structural and chemical analysis reveals that the optimized films exhibit strong Ga-O bonding, near-stoichiometric composition, high visible transparency, and a sharp ultraviolet (UV) absorption edge. Prototype solar blind photodetectors based on the β -Ga 2 O 3 /AlN/Si film display self-powered photoresponse and favorable optoelectronic characteristics, promising for real-time UV monitoring in harsh environments. These results provide a fundamental understanding and a practical, scalable route for integrating β -Ga 2 O 3 with mainstream Si technology, paving the way for advanced, energy-efficient optoelectronic and power electronic devices.