Carbon doping-induced defect centers in anodized alumina with enhanced optically stimulated luminescence

Anodized aluminum oxide (AAO) in amorphous form is shown to be a prospective phosphor for optically stimulated luminescence (OSL) by implanting 50 keV carbon ions at a fluence of 1 × 1016 ions/cm2 at room temperature. An almost 20-fold enhancement in continuous wave OSL (CW-OSL) sensitivity is obtained in carbon-doped AAO (C:AAO) by exposing to beta radiation, while an almost linear increase in CW-OSL intensity is recorded with increasing dose from 0.3 to 5 Gy. However, cathodoluminescence (CL) suggests an upsurge of oxygen vacancies, especially F+ and F22+ centers, at the cost of F center-related defects in C:AAO. Detailed X-ray photoelectron spectroscopy (XPS) analysis further reveals that the implanted carbon atoms can act as cationic impurities in AAO and stabilize the nearby F+ centers via substitution of Al3+ by C2+. The combined CL and XPS results are also shown to be capable of illustrating the CW-OSL response. This study would, therefore, be a benchmark for understanding the role of carbon in the substitutional sites of AAO for generating OSL active electron traps.