Ultrasmooth Silver Thin Films Deposited with a Germanium Nucleation Layer

Vj, Logeeswaran; Kobayashi, Nobuhiko P.; Islam, Maidul; Wu, Wei; Chaturvedi, Pratik; Fang, Nicholas X.; Wang, Shih-Yuan; Williams, R. Stanley

doi:10.1021/nl8027476

Cited by 284 publications

(177 citation statements)

References 31 publications

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“…The thickness of each Ag/SiO 2 layer was controlled at 30 nm 6 5 nm. To improve the surface roughness of these alternating layers, 2-nm-thick Ge layers were inserted between Ag and SiO 2 layers to enhance the wettability between these two materials [37][38][39] . In this experiment, we first deposited one-pair Ag/ SiO 2 layer on top of a 150-nm-thick Al film and fabricated a onedimensional (1D) patterned meta-absorber using focused ion beam (FIB) lithography, as shown in Fig.…”

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confidence: 99%

Broadband Absorption Engineering of Hyperbolic Metafilm Patterns

Song

Zeng

et al. 2014

Cleo: 2014

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Perfect absorbers are important optical/thermal components required by a variety of applications, including photon/thermal-harvesting, thermal energy recycling, and vacuum heat liberation. While there is great interest in achieving highly absorptive materials exhibiting large broadband absorption using optically thick, micro-structured materials, it is still challenging to realize ultra-compact subwavelength absorber for on-chip optical/thermal energy applications. Here we report the experimental realization of an on-chip broadband super absorber structure based on hyperbolic metamaterial waveguide taper array with strong and tunable absorption profile from near-infrared to mid-infrared spectral region. The ability to efficiently produce broadband, highly confined and localized optical fields on a chip is expected to create new regimes of optical/thermal physics, which holds promise for impacting a broad range of energy technologies ranging from photovoltaics, to thin-film thermal absorbers/emitters, to optical-chemical energy harvesting. E fficient optical absorbers are highly desired on the microscale where they can play a significant role in preventing crosstalk between optical interconnects on integrated photonic chips. In the thermal spectral region, waste heat is a major energy loss (including thermal radiation loss) in both industrial sectors and our daily life 1 . Particularly, as the density of integrated circuits in portable electronic/optoelectronic devices increases, on-chip thermal management becomes a critical research topic. To recover thermal radiation energy from objects with varying temperature, an efficient ultra-broadband absorber is an indispensable component. However, it is challenging to realize ultra-compact broadband absorber for on-chip optical, thermal and energy applications. In classic microwave electromagnetic (EM) approaches, EM wave absorbers have long been explored and widely utilized for important military applications, such as improving radar performance and providing concealment against others' radar systems 2 . In general, however, EM wave absorbers have been limited by their large, bulky dimensions. In recent years, intensive research efforts have been performed to realize compact/portable perfect metamaterial absorbers 3 . For instance, ideal omnidirectional absorption resonances at microwave, terahertz and mid-near infrared (IR) and visible frequencies have been demonstrated using metamaterial EM absorbers constructed by dielectric thin-films sandwiched by a patterned metal film and a flat metal ground plane 3 . Due to the critical coupling and/or impedance matching mechanism 4,5 , a narrow band of incident light can be efficiently coupled to magnetic resonant modes supported in these patterned metal-dielectric-metal metasurface structures. By tuning the geometric parameters of top metal patterns, the narrow band perfect absorption resonance can be tuned freely 3 . Currently, there is great interest in achieving 'black' on-chip metamaterials exhibiting broadband absorption...

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confidence: 99%

Broadband Absorption Engineering of Hyperbolic Metafilm Patterns

Song

Zeng

et al. 2014

Cleo: 2014

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“…A 3-nm germanium layer is evaporated as an adhesion layer, and followed by 30 nm gold evaporation. The Ge seed layer reduces the roughness of the gold surface from 3 to 1 nm, similar to the silver results in [5]. Each array contains identical dipole antennas with a 1-ȝm pitch.…”

Section: Optical Antenna Design and Fabricationmentioning

confidence: 89%

Characterization of Extended Width Optical Dipole Antennas

Seok

Jamshidi

Lakhani

et al. 2010

Conference on Lasers and Electro-Optics 2010

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“…46,66 Williams et al used a Ge seed layer to achieve a continuous Ag film. 65 Although the Ge deposition on the substrate also caused island growth, the density of the Ge nuclei was much larger and the islands were significantly smaller than those for Ag deposited without a seed layer on the substrate. This surface provided a heterogeneous nucleation site for the deposited Ag atoms.…”

Section: Seed Layermentioning

confidence: 99%

Transparent electrode of nanoscale metal film for optoelectronic devices

Lee

2015

J. Photon. Energy

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Abstract. This paper reviews the principles, impediments, and recent progress in the development of ultrathin flexible Ag electrodes for use in flexible optoelectronic devices. Thin Ag-based electrodes are promising candidates for next-generation flexible transparent electrodes. Thin Ag-based electrodes that have a microcavity structure show the best device performance, but have relatively low optical transmittance (OT) due to reflection and absorption of photons by the thin Ag; this trait causes problems such as spectral narrowing and change of emission color with viewing angle in white organic light-emitting diodes. Thinning the Ag electrode to < − 10 nm thickness (ultrathin Ag) is an approach to overcome these problems. This ultrathin Ag electrode has a high OT, while providing comparable sheet resistance similar to indium tin oxide. As the OT of the electrode increases, the cavity is weakened, so the spectral width of the emission and the angular color stability are increased.

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Ultrasmooth Silver Thin Films Deposited with a Germanium Nucleation Layer

Cited by 284 publications

References 31 publications

Broadband Absorption Engineering of Hyperbolic Metafilm Patterns

Broadband Absorption Engineering of Hyperbolic Metafilm Patterns

Characterization of Extended Width Optical Dipole Antennas

Transparent electrode of nanoscale metal film for optoelectronic devices

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