Pronounced visible luminescence in GaN by high-temperature anion implantation

Chemically robust III-nitrides (III-N) with bandgaps in the visible spectral range are critical for advancing emerging technologies such as solar-driven photocatalysis and optoelectronics. Conventional methods for bandgap reduction of GaN, such as increasing indium content in InGaN alloys, are limited by lattice mismatch strain-induced defects that compromise device performance. Incorporating small number of anions like arsenic (As) or antimony (Sb) offers an alternative through significant band bowing in GaN; however, achieving high visible emission efficiency remains challenging for in situ epitaxial incorporation due to thermodynamic barriers of limited solubility. This study demonstrates high-temperature (550 and 1000 °C) ion implantation as an effective strategy to tailor the spectral response of various GaN semiconductor structures into the visible range, achieving bright room-temperature photoluminescence at ∼485 and ∼550 nm for As- and Sb-related emissions, respectively. Notably, the implanted impurity concentration is only at the ∼1 × 1019 cm−3 level and localized at a depth of ∼30 nm below the surface. Based on density functional theory calculations, the observed As-related emission arises from a combined effect of valence band edge shifting by As replacing N isoelectronically and an Arsenic interstitial (Asi3+) defect level formation. The Sb-related emission was attributed only to the substitutional Sb in N site (SbN0) related band energy shift, as previously reported for epitaxial incorporation. This work establishes high-temperature ion implantation as a viable technique to enable effective concurrent impurity activation and crystal damage repair, opening pathways for deep-level defect and bandgap engineering in GaN for energy conversion and photonic and quantum applications.