Photoluminescence properties of Er-doped AlN films prepared by magnetron sputtering

Abstract

Er-doped aluminum nitride films, containing different Er concentrations, were obtained at room temperature by reactive radio frequency magnetron sputtering. The prepared samples show a nano-columnar microstructure and the size of the columns is dependent on the magnetron power. The Er-related photoluminescence (PL) was studied in relation with the temperature, the Er content and the microstructure. Steady-state PL, PL excitation spectroscopy and time-resolved PL were performed. Both visible and near infrared PL were obtained at room temperature for the as-deposited samples. It is demonstrated that the PL intensity reaches a maximum for an Er concentration equal to 1 at. % and that the PL efficiency is an increasing function of the magnetron power. Decay time measurements show the important role of defect related non radiative recombination, assumed to be correlated to the presence of grain boundaries. Moreover PL excitation results demonstrate that an indirect excitation of Er 3+ ions occurs for excitation wavelengths lower than 600 nm. It is also suggested that Er ions occupy at least two different sites in the AlN host matrix.

Erbium location into AlN films as probed by spatial resolution experimental techniques

“…This theoretical curve reflects quite the shape of the experimental curve of integrated photoluminescence as a function of the erbium content that could be measured on the present samples (published in [22]). Indeed, in both cases the curves increase until a maximum; which is followed by a drop.…”

“…The erbium doped aluminium nitride films were prepared by reactive radio frequency magnetron sputtering at room temperature. The films, containing different Er concentrations were earlier studied by steady state photoluminescence, photoluminescence excitation spectroscopy and time-resolved photoluminescence in a previous work [22]. The anterior work confirmed the classical behaviour of concentration quenching of these kinds of samples, by showing the existence of an optimal value for the infra-red photoluminescence signal for an erbium concentration at 1 at.%.…”

Ab initio investigation of the AlN:Er system

“…A variety of lanthanide elements in III-nitride semiconductors exhibit significant room temperature luminescence [1,2,3,4]. Hence, rare-earth (RE) doped nitrides are very promising for a series of optoelectronic applications among them flat panel displays and high contrast thick dielectric electroluminescent display devices [1,2].…”

Erbium-doped AlN epilayers synthesized by metal-organic chemical vapor deposition

“…The FWHM of the 1.54 µm peak is 24 nm compared to 47 nm for AlN:Er excited with λ exc = 195 nm. The narrowing of the 1.54 µm related emission PL lines when pumping resonantly into an intra-4f transition suggests that a specific class of Er 3+ ions was selectively excited [23]. Figure 5 compares the PL spectra of the IR emission near 1.5 µm of AlN:Er for λ exc = 263 nm at room temperature (above) and at 10 K (below).…”