Ultrathin thermoacoustic nanobridge loudspeakers from ALD on polyimide

Brown, Joseph J.; Moore, N. C.; Supekar, Omkar D.; Gertsch, Jonas C.; Bright, Victor M.

doi:10.1088/0957-4484/27/47/475504

Cited by 13 publications

(5 citation statements)

References 37 publications

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“…In terms of applications, this has been its principle distinction from other generation mechanisms. It has been observed in many thin film conductors 1–5 including graphene 6–10 , reduced graphene oxide 11, 12 and graphene foams 13, 14 . The exceptionally high thermal conductivity 15 and low heat capacity 16 of graphene make it the quintessential material for investigating thermoacoustics.…”

Section: Introductionmentioning

confidence: 99%

Multi-frequency sound production and mixing in graphene

Heath

Horsell

2017

Sci Rep

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The ability to generate, amplify, mix and modulate sound in one simple electronic device would open up a new world in acoustics. Here we show how to build such a device. It generates sound thermoacoustically by Joule heating in graphene. A rich sonic palette is created by controlling the composition and flow of the electric current through the graphene. This includes frequency mixing (heterodyning), which results exclusively from the Joule mechanism. It also includes shaping of the sound spectrum by a dc current and modulating its amplitude with a transistor gate. We show that particular sounds are indicators of nonlinearity and can be used to quantify nonlinear contributions to the conduction. From our work, we expect to see novel uses of acoustics in metrology, sensing and signal processing. Together with the optical qualities of graphene, its acoustic capabilities should inspire the development of the first combined audio-visual nanotechnologies.

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Section: Introductionmentioning

confidence: 99%

Multi-frequency sound production and mixing in graphene

Heath

Horsell

2017

Sci Rep

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“…Regarding thin metal film heaters and underlying thermal insulators, many studies have been conducted by using varied combinations: suspended Al wires-air (Niskanen et al, 2009), Si nanowires-polymer or -glass (Tian et al, 2011a), indium-tin-oxide film-glass (Daschewski et al, 2015), Si nanoparticles-sapphire (Odagawa et al, 2010), conducting polymers-glass (Tian et al, 2011b), thin Au film-porous polymer (Chitnis et al, 2012), thin Ag–Pd film-glass-Al 2 O 3 (Nishioka et al, 2015), carbon nanotube (CNT)-air (Xiao et al, 2011), or -grooved Si (Wei et al, 2013), graphene-polymer (Suk et al, 2012; Tian et al, 2014; Kim et al, 2016; Tao et al, 2016; Sbrockey et al, 2018), -porous Al 2 O 3 (Tian et al, 2012), or -glass (Fei et al, 2015), CNT-laser-scribed graphene-polymer (Yeklangi et al, 2018), and W-Al 2 O 3 -polymer (Brown et al, 2016). The basic characteristics of these devices are consistent with the theoretical analyses of the thermo-acoustic effect and its key factors (Hu et al, 2010, 2012a,b, 2014; Vesterinen et al, 2010; Daschewski et al, 2013; Lim et al, 2013; Yang and Liu, 2013; Wang et al, 2015; Tong et al, 2017; Xing et al, 2017).…”

Section: Emissive Properties and Applicationsmentioning

confidence: 99%

Emerging Functions of Nanostructured Porous Silicon—With a Focus on the Emissive Properties of Photons, Electrons, and Ultrasound

Koshida

Nakamura

2019

Front. Chem.

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Recent topics of application studies on porous silicon (PS) are reviewed here with a focus on the emissive properties of visible light, quasiballistic hot electrons, and acoustic wave. By exposing PS in solvents to pulse laser, size-controlled nc-Si dot colloids can be formed through fragmentation of the PS layer with a considerably higher yield than the conventional techniques such as laser ablation of bulk silicon and sol-gel precursor process. Fabricated colloidal samples show strong visible photoluminescence (~40% in quantum efficiency in the red band). This provides an energy- and cost-effective route for production of nc-Si quantum dots. A multiple-tunneling transport mode through nc-Si dot chain induces efficient quasiballistic hot electron emission from an nc-Si diode. Both the efficiency and the output electron energy dispersion are remarkably improved by using monolayer graphene as a surface electrode. Being a relatively low operating voltage device compatible with silicon planar fabrication process, the emitter is applicable to mask-less parallel lithography under an active matrix drive. It has been demonstrated that the integrated 100 × 100 emitter array is useful for multibeam lithography and that the selected emission pattern is delineated with little distortion. Highly reducing activity of emitted electrons is applicable to liquid-phase thin film deposition of metals (Cu) and semiconductors (Si, Ge, and SiGe). Due to an extremely low thermal conductivity and volumetric heat capacity of nc-Si layer, on the other hand, thermo-acoustic conversion is enhanced to a practical level. A temperature fluctuation produced at the surface of nc-Si layer is quickly transferred into air, and then an acoustic wave is emitted without any mechanical vibrations. The non-resonant and broad-band emissivity with low harmonic distortions makes it possible to use the emitter for generating audible sound under a full digital drive and reproducing complicated ultrasonic communication calls between mice.

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“…However, most of these prior numerical modeling efforts stem from the need to represent their empirical experimental data in a reduced form. Therefore, they typically omit various physics in the simulation environment, which are shown to play a potentially important role under different investigations (Aliev et al, 2018;Brown et al, 2016). Instead of relying on these simplification-driven paradigms and toward creating a generalized bottom-up approach, the paper authored by Guiraud et al (2019a) proposes a novel modular framework that can describe an arbitrary multi-layered thermophone device, where each layer is either a solid or a fluid.…”

Section: Introductionmentioning

confidence: 99%

Guidelines for higher efficiency supported thermo-acoustic emitters based on periodically Joule heated metallic films

Leizeronok

Losin

Kleiman

et al. 2023

The Journal of the Acoustical Society of America

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The paper focuses on the evaluation of the impact associated with various geometrical and material properties on the overall acoustic performance of generic multi-layer thermo-acoustic sources. First, a generalized numerical framework is developed using a state-of-the-art thermo-acoustic emission model for multi-layered devices and is used to forecast the effects associated with different parameters (thickness, density, thermal conductivity, and specific heat capacity), based on a set of 65 536 simulated architectures. Then, the acoustic facility is designed, assembled, and instrumented, and the findings of the simulation campaign are validated against experimental measurements for 32 different samples, manufactured via various vacuum deposition techniques. The results of the experimental campaign corroborate the simulation's prediction and indicate that the variables that have the strongest impact on the thermo-acoustic performance are the thicknesses of the substrate and thermophone layers, as well as the backing's thermal conductivity. Finally, the experimental results are directly comparable with the simulation predictions and the deviation between the two values is within the limits of the experimental accuracy, with an average deviation of 12% (maximal divergence of 28%) and best absolute performance of [Formula: see text] when measured from a distance of [Formula: see text]. Overall, the findings provide an insight into the effect of analyzed properties and offer a set of tangible guidelines that can be applied in the future toward the design optimization process that can potentially result in higher-efficiency thermophone-on-substrate thermo-acoustic emitters.

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Ultrathin thermoacoustic nanobridge loudspeakers from ALD on polyimide

Cited by 13 publications

References 37 publications

Multi-frequency sound production and mixing in graphene

Multi-frequency sound production and mixing in graphene

Emerging Functions of Nanostructured Porous Silicon—With a Focus on the Emissive Properties of Photons, Electrons, and Ultrasound

Guidelines for higher efficiency supported thermo-acoustic emitters based on periodically Joule heated metallic films

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