English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In the prospect of understanding the photoluminescence mechanisms of AlNfilms doped with erbium and targeting photonic applications we have synthesizednon doped and Er-doped AlN films with different crystallized nanostructures byusing PVD magnetron sputtering. Their crystalline morphology and their visiblephotoluminescence properties were precisely measured.Due to the weakcross-section absorption of rare earths like erbium, it is necessary to obtainan efficient energy transfer mechanism between the host matrix and the rareearth to obtain high luminescence efficiency. Our strategy is then to elaboratesome nanostructures that could introduce additional intermediate electroniclevels within the gap thanks to the presence of structural defects (pointdefects, grain boundaries{\ldots}) and could lead to energy transfer from theAlN matrix to the rare earth.Doped and non-doped AlN films were prepared byradio frequency magnetron sputtering by using different experimental conditionsthat will be detailed. It will notably be shown how a negative polarization ofsamples during deposition allows obtaining crystalline morphologies rangingfrom the classical columnar structure to a highly disordered polycrystallinestructure with grains of several nanometers (nearly amorphous). Thenanostructures of the films could be categorized in three types: 1) type 1 wasnanocolumnar (width of column ~ 15 nm), 2) type 2 was made of short columns(width of column ~ 10 nm) and 3) the last type was made of equiaxednanocrystallites (size of grains ~3-4 nm).High-resolution photoluminescencespectroscopy was performed to characterize their optical behaviour. The sampleswere excited by the laser wavelengths at 458, 488 or 514 nm. A broadphotoluminescence band was observed centred around 520 nm in columnar samples.In the same energy range, the highly resolved spectra also showed several sharpemission peaks. This fine structure could be attributed to erbium transitions.This fine structure tended to disappear going from type 1 to type 3 samples.Indeed, the relative intensity of the peaks decreased and their full width athalf maximum increased. This change could be related to the density of defectsthat increased when the size of the grains decreased. The photoluminescenceproperties of the films in the visible range will be discussed in relation withtheir structure.

Optical characterization of nanocrystallized AlN:Er films prepared by magnetron sputtering