Luminescence studies on swift heavy ion irradiated nanocrystalline aluminum oxide

Pellets of nanocrystalline aluminum oxide synthesized by a combustion technique are irradiated with 120 MeV Au⁹⁺ ions for fluence in the range 5×10¹¹-1×10¹³ ions cm⁻². Two photoluminescence (PL) emissions, a prominent one with peak at ∼525 nm and a shoulder at ∼465 nm are observed in heat treated and Au⁹⁺ ion irradiated aluminum oxide. The 525 nm emission is attributed to F₂²⁺-centers. The PL intensity at 525 nm is found to increase with increase in ion fluence up to 1×10¹² ions cm⁻² and decreases beyond this fluence. Thermoluminescence (TL) of heat-treated and swift heavy ion (SHI) irradiated aluminum oxide gives a strong and broad TL glow with peak at ∼610 K along with a weak shoulder at 500 K. The TL intensity is found to increase with Au⁹⁺ ion fluence up to 1×10¹³ ions cm⁻² and decreases beyond this fluence.