Electroluminescence properties of the Gd~(3+) ultraviolet luminescent centers in SiO_2 gate oxide layers

摘要

Electroluminescence (EL) properties in the ultraviolet (UV) range were studied on Gd-implanted indium tin oxide/SiO_2:Gd/Si metal-oxide-semiconductor light emitting devices. The efficient UV line at 316 nm from Gd~(3+) centers shows a maximum power density of 2 mW/cm~2 and a quantum efficiency above 5%. The Gd~(3+) luminescent center has an excitation cross section above 7.4 x 10~(-15) cm~2 with an EL decay time around 1.6 ms at a Gd concentration of 3%. A decrease of the EL efficiency is observed by a cross relaxation at a high Gd concentration and by clustering of Gd atoms at an annealing temperature of 1000℃. A strong quenching of the UV EL due to electron trapping around optically active Gd~(3+) centers is observed during the injection of hot electrons.