Yellow electroluminescence from sputtering synthesized aluminum nitride nanocomposite thin film containing aluminum nanocrystals

In this work, visible electroluminescence (EL) from aluminum nitride (AlN) thin film containing aluminum nanocrystals (nc-Al) prepared by a radio frequency sputtering technique is reported. The yellow EL shows a spectrum peaked at 565 nm. A linear relationship between the EL and the current transport in the nc-Al/AlN nanocomposite thin film is observed, and both the current transport and the EL intensity show a power-law dependence on the gate voltage. The current conduction is explained by the carrier conduction in the percolation networks of tunneling paths formed by the nc-Al arrays, and the light emission is attributed to the radiative recombination of the injected electrons and holes via the deep-level defects at the locations of nc-Al along the tunneling paths. The EL intensity is also temperature dependent. The enhancement in EL intensity at the elevated temperatures is observed and associated with the enhanced current conduction. At both room temperature and elevated temperatures, there is no obvious decay in the EL intensity for up to 10 on/off cycles, indicating the excellent light emission endurance. The results in this work suggest the potential applications of the nc-AlN/AlN nanocomposite thin film in the low-cost and CMOS-compatible optoelectronic devices.