Yellow electroluminescence from sputtering synthesized aluminum nitride nanocomposite thin film containing aluminum nanocrystals
M. Yang, T.P. Chen, Y. Liu, J.I. Wong
Nanyang Technological University, SG
Keywords: aluminum nitride, aluminum nanocrystal, electroluminescence, light emitting device
Abstract:In this work, visible electroluminescence (EL) from aluminum nitride (AlN) thin films 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 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 temperature is observed and associated with the enhanced current conduction. At both room temperature and elevated temperature, there is no decay in the EL intensity for up to 10^6 on/off cycles, indicating the excellent light emission endurance. The results in this work suggest the potential applications of the nc-AlN/AlN thin film in the low-cost and CMOS-compatible optoelectronic devices.