Integration of Self-Assembled Porous Alumina and Distributed Bragg Reflector for Light Trapping in Si Photovoltaic Devices

Sheng, Xing; Liu, Jifeng; Coronel, Naomi C.; Agarwal, Anuradha M.; Michel, Jürgen; Kimerling, Lionel C.

doi:10.1109/lpt.2010.2060717

Cited by 42 publications

(31 citation statements)

References 10 publications

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“…Although periodic nanostructures can also be obtained by other nanostructure fabrication techniques represented by photolithography, the ease of anodizing without any expensive equipment is very important for various nanotechnology researchers. Using characteristic nanostructural features, anodic porous aluminum oxide has been widely investigated for many nanoapplications: antireflection structures [134][135][136][137][138][139], reflectors [140][141][142], diodes [143][144][145], plasmonic devices [146][147][148][149], sensors [150][151][152], containers [153,154], catalyst supports [155][156][157], masks [158][159][160], emulsification filters [161,162], magnetic recording media [163][164][165], memory devices [166][167][168], photovoltaic devices [169], nanomeshes [170], etc. Greatly wide-ranging applications of anodic porous oxides have been reported to date.…”

Section: Various Nanoapplications Based On the Porous Aluminum Oxidementioning

confidence: 99%

Porous Aluminum Oxide Formed by Anodizing in Various Electrolyte Species

Kikuchi¹,

Nakajima²,

Nishinaga³

et al. 2015

CNANO

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Anodizing of aluminum and its alloys is widely investigated and used for corrosion protection, electronic devices, and micro-/nanostructure fabrication. Anodizing of aluminum in acidic solutions causes formation of porous aluminum oxide films, which consists of numerous hexagonal cells perpendicular to the aluminum substrate, and each cell has nanoscale pores at its center. Recently, highly ordered porous aluminum oxide has been widely investigated for various novel nanoapplications. In this review article, we introduce the fundamentals of anodic oxide films including barrier and porous oxides. Then, we summarize the electrolyte species used so far for porous oxide fabrication and describe the self-ordering conditions during anodizing in these electrolyte solutions. Fabrication of highly ordered porous oxides through the vertical section can be achieved by a two-step anodizing and nanoimprint technique. Various nanoapplications based on the ordered porous oxide are also introduced.

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Section: Various Nanoapplications Based On the Porous Aluminum Oxidementioning

confidence: 99%

Porous Aluminum Oxide Formed by Anodizing in Various Electrolyte Species

Kikuchi¹,

Nakajima²,

Nishinaga³

et al. 2015

CNANO

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“…Previously, we reported fabrication of gratings using self-assembled porous alumina for light trapping in silicon solar cells. [ 8 ] However, the low refractive index of alumina ( n ∼ 1.7) has limited the diffraction effect. Furthermore, in production solar cells the electrolyte used in the anodization process reacts with the TCO resulting in device degradation.…”

mentioning

confidence: 99%

“…[ 12 ] The PAM has been reported to pattern Al surfaces, [ 13 ] or be directly fabricated in the back of Si as a grating layer. [ 8 ] Due to the instability of ZnO during the anodization we employ PAM as a deposition mask. [ 14 ] By anodizing at a constant DC voltage of 280 V in a citric acid solution, [ 15 ] a PAM structure with a period of about 700 nm and a porosity of nearly 50% was fabricated, as shown in Figure 3 a.…”

mentioning

confidence: 99%

Design and Non‐Lithographic Fabrication of Light Trapping Structures for Thin Film Silicon Solar Cells

et al. 2010

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Along with increasing fossil-fuel consumption and greenhouse gas emissions, sustainable energy research has been a global topic for many years. Among all the renewable energy sources, solar energy has been attracting widespread attention because of its abundance, stability and environmental friendliness. Nowadays, more than 90% of the photovoltaic market is dominated by wafer-based silicon solar cells. The cost of this technique, which is dominated by the starting material, is diffi cult to reduce. [ 1 ] Thin fi lm silicon solar cells have an active layer of only several micrometers thick and are believed to be a promising candidate for further cost reduction while maintaining the advantages of bulk silicon. [ 2 ] However, the effi ciency of thin fi lm silicon solar cells critically depends on optical absorption in the silicon layer since silicon has low absorption coeffi cient in the red and near-infrared (IR) wavelength ranges due to its indirect bandgap nature. Therefore, an effective light trapping design is indispensable to achieve high effi ciency modules. To address this problem, several methods are used in current technology, for example, traditional schemes such as textured transparent conductive oxide (TCO) and metal refl ector. [ 3 ] These methods are diffi cult to precisely control and optimize the textured surface. In addition, some other issues should be considered such as enhanced surface recombination due to the roughness of silicon layer [ 4 ] and parasitic loss at the TCO/metal interface. [ 5 ] One, two and three dimensional photonic crystals have also been proposed to enhance the light trapping, [ 6 ] but this design is very diffi cult to be implemented experimentally. A practical approach for light trapping has been demonstrated using diffractive grating structures on the backside of a silicon cell. [ 7 ] However, interference lithography and high temperature processing were usually employed in fabricating this structure, limiting its scalability to large area applications. Previously, we reported fabrication of gratings using self-assembled porous alumina for light trapping in silicon solar cells. [ 8 ] However, the low refractive index of alumina ( n ∼ 1.7) has limited the diffraction effect. Furthermore, in production solar cells the electrolyte used in the anodization process reacts with the TCO resulting in device degradation. To achieve a stronger light trapping effect in production Si thin fi lm solar cell structures while exploiting a more controllable and reliable method for fabrication, here we design a backside photonic structure consisting of a high-index-contrast diffraction grating and a distributed Bragg Refl ector (DBR). We optimize the structure in a thin fi lm microcrystalline silicon ( μ c-Si) solar cell, and implement the design experimentally using a self-assembled mask to demonstrate signifi cantly enhanced cell effi ciency due to increased optical path length. The light trapping structures lead to a signifi cant increase of photon absorption in the red and near-infrared ...

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“…This happens because of two main factors: (i) its porous structure is adequate for integrating the necessary fluidic circuits with the optical setup and (ii) its great surface-to-volume ratio permits a great amplification factor of the changes in the surface, even for small amounts of the species to be detected. Nevertheless, optical properties of p-AAO are also the basis of other applications not directly related to sensing, as for instance the extraction of light from LEDs [79,96] (where the p-AAO nanostructure serves as a texturizing template for the LED surface), the generation of laser emission [76] (where the self-arrangement of pores contributes to create cavity modes to amplify laser light emitted by a gain material infiltrated within the pores), to texturize surfaces and interfaces of photovoltaic cells to improve light absorption or charge collection in the energy conversion process [97], or even to create unique photonic barcodes for labeling applications [98]. Doing an extensive review of all the applications based on the optical properties would require a much longer extent than this chapter.…”

Section: Photonic Properties: Interaction Of Light With P-aao Nanostrmentioning

confidence: 99%

“…Furthermore, the nanostructure permits a deeper penetration of light into the material with a consequent further increase in quantum efficiency around the wavelength of 400 nm. In the work by Sheng et al [97], a p-AAO grown on the backside of a silicon-based PV device combined with a DBR structure composed of alternating layers of deposited Si and SiO 2 , leads to an increase in absorption at the near-IR. The p-AAO acts as a subwavelength grating that scatters the light back-reflected by the Si-SiO 2 DBR generating the increase in absorption.…”

Section: Porous Anodic Aluminum Oxide In Photon-energy Conversionmentioning

confidence: 99%

Optical Properties of Nanoporous Anodic Alumina and Derived Applications

et al. 2015

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Inexpensive formation of periodically ordered structures with periodicities and feature sizes lower than 100 nm has triggered a vast amount or research in recent years. Of particular interest in nanotechnology is the nanoporous alumina, which can be produced with a self-organized arrangement of pores in the adequate anodization conditions. Most of the interest of this material is based in its outstanding physical and chemical and properties, and more specifically in its optical properties. The interaction of light with the nanostructured porous alumina gives rise to a wealth of optical properties that have their interest both in research level and also in application. In this work we aim at giving an extensive review of the published research on the optical properties of nanoporous alumina. The review will account for the different studied optical properties of this material such as the existence of a photonic stop band originated from its quasi-random nanostructure, the interferometric and light guiding properties that can be applied to biosensing, the structure nanoengineering to achieve more complex photonic behaviour such as distributed-Bragg reflectors or rugate filters, and the photoluminescence properties. In a second part, a summary of the different applications proposed on the basis of these properties, such as in biotechnology or energy will be given. IntroductionAmong the different features and properties of porous anodic alumina (p-AAO), its optical properties are of special interest and have been the subject of very intensive research. The interaction of light with p-AAO can be analyzed from different points of view: the material interaction, the porous structure interaction or the relation of geometrical features of the nanostructure (periodicity or quasi-periodicity, distance

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Integration of Self-Assembled Porous Alumina and Distributed Bragg Reflector for Light Trapping in Si Photovoltaic Devices

Cited by 42 publications

References 10 publications

Porous Aluminum Oxide Formed by Anodizing in Various Electrolyte Species

Porous Aluminum Oxide Formed by Anodizing in Various Electrolyte Species

Design and Non‐Lithographic Fabrication of Light Trapping Structures for Thin Film Silicon Solar Cells

Optical Properties of Nanoporous Anodic Alumina and Derived Applications

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