Defect formation and modification of optical properties in β-Ga₂O₃ via carbon ion irradiation

Precisely regulating the optical properties of β-Ga₂O₃ crystals is critical for advancing optoelectronic devices such as solar-blind detectors, optical modulators, and Schottky barrier diodes. This study employed 15 MeV carbon (C) ions to irradiate β-Ga2O3, revealing lattice defect aggregation at a depth of 6 ∼ 7 µm, accompanied by increased surface root-mean-square roughness, compressive strain-induced lattice distortion, and elevated oxygen vacancy concentration. Irradiation-induced defects act as non-radiative recombination centers, suppressing photoluminescence (PL) intensity. Additionally, these defects contribute to reduced ultraviolet (UV) absorption and bandgap narrowing in β-Ga2O3. This work demonstrates the profound impact of C-ion irradiation on the optical properties of β-Ga2O3, offering insights into ion beam engineering for ultra-wide bandgap semiconductor optimization.