Intense ultraviolet cathodoluminescence at 318 nm from Gd3+-doped AlN

Abstract

We present investigations of Gd-implanted aluminum nitride, studied with cathodoluminescence (CL) as well as time-resolved CL in the temperature range 12–300 K. Luminescence due to intra-4f electron transitions of Gd3+ is dominated by the P7/26→S7/28 transition between the first excited state and the ground state of Gd3+ detected at around 318 nm. Time-resolved CL of the P7/26 level monitoring the P7/26→S7/28 transition shows a temperature-dependent lifetime which decreases from 0.76 ms at 12 K to 0.69 ms at 300 K, in contrast to an increasing intensity of the P7/26→S7/28 transition by a factor of more than 3.5 in the same temperature range. The decay is of the Inokuti–Hirayama-type indicating energy transfer between Gd3+ ions. Due to the overall weak splitting of the P7/26 and S7/28 multiplets phonon replica with energies of 100 and 588 cm−1 can be assigned.