Fabrication of large area subwavelength antireflection structures on Si using trilayer resist nanoimprint lithography and liftoff

Yu, Zhaoning; Gao, Hongwu; Wu, Wei; Ge, Haixiong; Chou, Stephen Y.

doi:10.1116/1.1619958

Cited by 231 publications

(144 citation statements)

References 16 publications

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“…The performance can be further improved from the step profile created by nanopillars by tapering the structures into nanocones to produce a continuous graded index profile. For example, Yu and colleages [ 25 ] devised a technique for forming very regular silicon nanocones by nano-imprinting a pattern on a tri-layer resist, multistep reactive ion etching to transfer the pattern through the resist, depositing and lifting off metal to create a hard mask, and further reactive ion etching to create the nanocones. Reflectivity of < 5% was achieved across the solar spectrum for cones with a lateral period of 200 nm and a height of 520 nm.…”

Section: Mesostructuresmentioning

confidence: 99%

Nanostructures for photon management in solar cells

Narasimhan

Cui

2013

Nanophotonics

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Abstract:The concurrent development of high-performance materials, new device and system architectures, and nanofabrication processes has driven widespread research and development in the field of nanostructures for photon management in photovoltaics. The fundamental goals of photon management are to reduce incident light reflection, improve absorption, and tailor the optical properties of a device for use in different types of energy conversion systems. Nanostructures rely on a core set of phenomena to attain these goals, including gradation of the refractive index, coupling to waveguide modes through surface structuring, and modification of the photonic band structure of a device. In this review, we present recent developments in the field of nanostructures for photon management in solar cells with applications across different materials and system architectures. We focus both on theoretical and numerical studies and on progress in fabricating solar cells containing photonic nanostructures. We show that nanoscale light management structures have yielded real efficiency gains in many types of photovoltaic devices; however, we note that important work remains to ensure that improved optical performance does not come at the expense of poor electrical properties.

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Section: Mesostructuresmentioning

confidence: 99%

Nanostructures for photon management in solar cells

Narasimhan

Cui

2013

Nanophotonics

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“…9,10 To obtain high-performance solar cells it is critical to fabricate periodic SWSs to eliminate all diffraction-order light. So far periodic SWSs have been patterned on Si through various methods, such as electron-beam lithography, 11 laser interference lithography, 12 nanoimprint lithography, 13 and electrochemical etching technique. 14 However, these techniques are restricted from the practical applications due to their expensive equipment, complex procedures, and disordered alignment.…”

Section: Introductionmentioning

confidence: 99%

Surface profile-controlled close-packed Si nanorod arrays for self-cleaning antireflection coatings

Lin

Wang

Lin

et al. 2009

Journal of Applied Physics

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We demonstrate the fabrication of surface profile-controlled close-packed Si nanorod arrays ͑NRAs͒, using a scalable and integrated circuit compatible process combining colloidal lithography and reactive ion etching. Si NRAs exhibit broadband, omnidirectional, and polarization-insensitive antireflection ͑AR͒ properties and enhance the hydrophobicity. The effect of surface profiles of periodic NRAs on the AR and hydrophobicity was investigated systematically. The Si NRAs function as both self-cleaning and AR layers, which offer a promising approach to enhance the solar cell energy conversion efficiency.

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“…The saturating dye concentration is 1 dye molecule per 4 base pairs, so at our dye concentration (40% of full dying) we expect an increase of 13%, yielding a The channels are shown sealed to a fused silica coverslip (the sealing was accomplished via direct quartzquartz bonding). Imprinted nanochannels are densely packed with a periodicity of 200 nm and width that can be varied from 150 to 35 nm using a novel trilayer technique (wider channels can also be fabricated with a correspondingly higher period) [18]. [16] Their fluctuations were then recorded with a Pentamax ICCD camera (Roper Scientific) on a Nikon Eclipse TE300 microscope using a 100 N.A.1.4 oil immersion objective (Nikon).…”

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confidence: 99%

“…The crossover regime is important as it is likely to occur within the range of scales used in devices: the persistence length of double stranded DNA (dsDNA) is roughly 50 nm in standard electrophoresis buffers [16]. The nanochannels used in this study were nanofabricated on fused silica substrates using a combination of two techniques: (1) nanoimprint lithography [17,18] and (2) electron beam lithography using a Leica/Cambridge EBMF system at the Cornell Nanofabrication Facility (CNF). Figure 2 shows images of sealed channels.…”

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confidence: 99%

Statics and Dynamics of Single DNA Molecules Confined in Nanochannels

et al. 2005

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The successful design of nanofluidic devices for the manipulation of biopolymers requires an understanding of how the predictions of soft condensed matter physics scale with device dimensions. Here we present measurements of DNA extended in nanochannels and show that below a critical width roughly twice the persistence length there is a crossover in the polymer physics. DOI: 10.1103/PhysRevLett.94.196101 PACS numbers: 81.16.Nd, 82.35.Lr, 82.39.Pj Top-down approaches to nanotechnology have the potential to revolutionize biology by making possible the construction of chip-based devices that can not only detect and separate single DNA molecules by size [1-4] but also-it is hoped in the future-actually sequence at the single molecule level [5]. While a number of top-down approaches have been proposed, all these approaches have in common the confinement of DNA to nanometer scales, typically 5-200 nm. Confinement alters the statistical mechanical properties of DNA. A DNA molecule in a nanochannel will extend along the channel axis to a substantial fraction of its full contour length [1,6]. Moreover, confinement is expected to alter the Brownian dynamics of the confined molecule [1]. While the study of confined DNA is interesting from a physics perspective, it is also critical for device design, potentially leading to new applications of nanoconfinement (for example, the use of nanochannels to prestretch and stabilize DNA before threading through a nanopore [5]). Moreover, available models [7][8][9][10][11] and simulations [12,13] are unable to account for the effect of varying confinement over the entire range of scales used in nanodevices. The theory gives asymptotic results valid only in limits that are not necessarily compatible with device requirements [1].Consider a DNA molecule of contour length L, width w, and persistence length P confined to a nanochannel of width D with D less than the radius of gyration of the molecule. When D P, the molecule is free to coil in the nanochannel and the elongation is due entirely to excluded volume interactions between segments of the polymer greatly separated in position along the backbone (see Fig. 1). de Gennes developed a scaling argument for the average extension of a confined self-avoiding polymer [8,12] which was later generalized by Schaefer and Pincus to the case of a persistent self-avoiding polymer [14]. The de Gennes theory predicts an extension r that scales with D in the following way:If the aspect ratio of the channel is not unity, i.e., the width D D 1 does not equal the depth D 2 , then Eq. (1) is still valid provided that D is replaced by the geometric average of the dimensions. As the channel width drops below the persistence length, the physics is dominated not by excluded volume but by the interplay of confinement and intrinsic DNA elasticity. In the strong confinement limit D P, backfolding is energetically unfavorable and contour length is stored exclusively in deflections made by the polymer with the walls. These deflections occur on average over th...

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Fabrication of large area subwavelength antireflection structures on Si using trilayer resist nanoimprint lithography and liftoff

Cited by 231 publications

References 16 publications

Nanostructures for photon management in solar cells

Nanostructures for photon management in solar cells

Surface profile-controlled close-packed Si nanorod arrays for self-cleaning antireflection coatings

Statics and Dynamics of Single DNA Molecules Confined in Nanochannels

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