Thickness-dependent optical properties of aluminum nitride films for mid-infrared wavelengths

Beliaev, Leonid Yu.; Shkondin, Evgeniy; Lavrinenko, Andrei V.; Takayama, Osamu

doi:10.1116/6.0000884

Cited by 23 publications

(14 citation statements)

References 79 publications

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“…This result does not take into account any potential thickness dependence of the permittivity, which could play a role at such thicknesses; however optical response can remain quite strong (bulk-like), in extremely thin layers in van der Waals and/or phononic materials, down to nanoscale thicknesses. 40,59 This is especially true in monolayer and few-layer TMDCs, 36,37 indicating remarkable potential for light-matter interaction at the ultimate ultrathin limit.…”

Section: ■ Resultsmentioning

confidence: 99%

Perfect Absorption at the Ultimate Thickness Limit in Planar Films

Sakotic,

Ware,

Povinelli

et al. 2023

ACS Photonics

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Reducing device volume is one of the key requirements for advanced nanophotonic technologies; however, this demand is often at odds with designing highly absorbing elements which usually require sizable thicknesses, such as for detector and sensor applications. Here we theoretically explore the thickness limitations of perfectly absorbing resonant systems and show surprisingly low bounds on minimal required thicknesses for total light absorption in thin planar films. We present a framework for understanding, predicting, and engineering topologically protected perfect absorption in a wide range of resonantly absorbing materials. The proposed analytical approach leads to a simple relation between a perfect absorber’s thickness and dielectric function loss, which also serves as a guide for determining the absorption potential of existing and emerging materials at the ultimate thickness limit. The presented results offer new insights into the extremes of light–matter interaction and can facilitate the design of ultrasensitive light absorbers for detector and sensor systems.

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Section: ■ Resultsmentioning

confidence: 99%

Perfect Absorption at the Ultimate Thickness Limit in Planar Films

Sakotic,

Ware,

Povinelli

et al. 2023

ACS Photonics

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“…Figure shows the refractive index used to model the AlN layer, along with the measured and modeled SE spectra for this final version of the model, showing a good match between the measured and modeled spectra. The modeled trends in optical constants with wavelength are consistent with previously determined values of AlN samples. − …”

Section: Resultsmentioning

confidence: 99%

Monitoring of the Initial Stages of Diamond Growth on Aluminum Nitride Using In Situ Spectroscopic Ellipsometry

et al. 2023

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The high thermal conductivity of polycrystalline diamond makes it ideally suited for thermal management solutions for gallium nitride (GaN) devices, with a diamond layer grown on an aluminum nitride (AlN) interlayer atop the GaN stack. However, this application is limited by the thermal barrier at the interface between diamond and substrate, which has been associated with the transition region formed in the initial phases of growth. In this work, in situ spectroscopic ellipsometry (SE) is employed to monitor early-stage microwave plasma-enhanced chemical vapor deposition diamond growth on AlN. An optical model was developed from ex situ spectra and applied to spectra taken in situ during growth. Coalescence of separate islands into a single film was marked by a reduction in bulk void fraction prior to a spike in sp2 fraction due to grain boundary formation. Parameters determined by the SE model were corroborated using Raman spectroscopy and atomic force microscopy.

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“…As the first step, the complex permittivities of the 500 μm thick double-sided polished Si substrate were determined from the free-space reflection spectra. The retrieved parameters and the fitted spectrum are presented in the Supporting Information (Supporting Information, Table S2 and Figure S1), and a detailed description of the entire procedure can be found elsewhere. , …”

Section: Resultsmentioning

confidence: 99%

Titanium Nitride Nanotrench Metasurfaces for Mid-infrared Chemical Sensing

Beliaev,

Shkondin,

Lavrinenko

et al. 2023

ACS Appl. Opt. Mater.

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Mid-infrared vibrational spectroscopy exploits characteristic infrared absorption features of molecules and chemical bondings, providing a powerful sensing tool to detect molecules. However, the challenge lies in the relatively weak light−matter interaction, leading to small absorption signatures. Plasmonic metasurfaces made of metal nanostructures are able to localize light, enhance light−matter interactions, and thus enable increasing mid-infrared light absorption by molecules. We demonstrate the enhancement of infrared absorption of vanillin molecules by plasmonic titanium nitride trench-based metasurfaces with a high aspect ratio, which outperforms that of silicon samples with similar geometrical parameters. A 70% extra absorption signal by plasmonic structures is due to stronger electric fields within the deep subwavelength trenches. Titanium nitride trench nanostructures may serve as a highly sensitive chemical sensing platform for mid-infrared absorption spectroscopy.

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Thickness-dependent optical properties of aluminum nitride films for mid-infrared wavelengths

Cited by 23 publications

References 79 publications

Perfect Absorption at the Ultimate Thickness Limit in Planar Films

Perfect Absorption at the Ultimate Thickness Limit in Planar Films

Monitoring of the Initial Stages of Diamond Growth on Aluminum Nitride Using In Situ Spectroscopic Ellipsometry

Titanium Nitride Nanotrench Metasurfaces for Mid-infrared Chemical Sensing

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