Radial junction silicon wire array solar cells fabricated by gold-catalyzed vapor-liquid-solid growth

Kendrick, Chito; Yoon, H P; Yuwen, Yu; Barber, Greg D.; Shen, Haoting; Mallouk, Thomas E.; Dickey, Elizabeth C.; Mayer, Theresa S.; Redwing, Joan M.

doi:10.1063/1.3496044

Cited by 82 publications

(80 citation statements)

References 25 publications

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“…Semiconductor nanowires (NWs) have exhibited promising efficiencies as single NW photovoltaic elements (8)(9)(10)(11)(20)(21)(22) and as vertical arrays configured as photovoltaic (23)(24)(25)(26) and photoelectrochemical (27,28) solar cells, where the vertical array has been used to enhance light absorption (29). In the case of Si-based nanostructures, where Si photovoltaics represent benchmark systems with attractive material abundance and cost (30), the efficiency of NW devices has typically been limited by poor electrical performance and lack of tunable control of absorption properties at specific and broadband wavelengths.…”

mentioning

confidence: 99%

Coaxial multishell nanowires with high-quality electronic interfaces and tunable optical cavities for ultrathin photovoltaics

Kempa

Cahoon

Kim

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

198

219

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Silicon nanowires (NWs) could enable low-cost and efficient photovoltaics, though their performance has been limited by nonideal electrical characteristics and an inability to tune absorption properties. We overcome these limitations through controlled synthesis of a series of polymorphic core/multishell NWs with highly crystalline, hexagonally-faceted shells, and well-defined coaxial p-type∕ n-type (p∕n) and p∕intrinsic∕n (p∕i∕n) diode junctions. Designed 200-300 nm diameter p∕i∕n NW diodes exhibit ultralow leakage currents of approximately 1 fA, and open-circuit voltages and fillfactors up to 0.5 V and 73%, respectively, under one-sun illumination. Single-NW wavelength-dependent photocurrent measurements reveal size-tunable optical resonances, external quantum efficiencies greater than unity, and current densities double those for silicon films of comparable thickness. In addition, finite-difference-time-domain simulations for the measured NW structures agree quantitatively with the photocurrent measurements, and demonstrate that the optical resonances are due to Fabry-Perot and whispering-gallery cavity modes supported in the high-quality faceted nanostructures. Synthetically optimized NW devices achieve current densities of 17 mA∕cm 2 and power-conversion efficiencies of 6%. Horizontal integration of multiple NWs demonstrates linear scaling of the absolute photocurrent with number of NWs, as well as retention of the high open-circuit voltages and short-circuit current densities measured for single NW devices. Notably, assembly of 2 NW elements into vertical stacks yields short-circuit current densities of 25 mA∕cm 2 with a backside reflector, and simulations further show that such stacking represents an attractive approach for further enhancing performance with projected efficiencies of >15% for 1.2 μm thick 5 NW stacks.nanodevices | nanomaterials | nanophotonics | optical nanocavities | solar cells N anostructures and nanostructured materials may enable next-generation solar cells by providing for efficient charge separation (1-16) and tunable optical absorption (11,(17)(18)(19). Semiconductor nanowires (NWs) have exhibited promising efficiencies as single NW photovoltaic elements (8)(9)(10)(11)(20)(21)(22) and as vertical arrays configured as photovoltaic (23-26) and photoelectrochemical (27, 28) solar cells, where the vertical array has been used to enhance light absorption (29). In the case of Si-based nanostructures, where Si photovoltaics represent benchmark systems with attractive material abundance and cost (30), the efficiency of NW devices has typically been limited by poor electrical performance and lack of tunable control of absorption properties at specific and broadband wavelengths. For example, previous reports of coaxial (8) and axially modulated (9) p-i-n single-NW photovoltaic devices yielded open-circuit voltages (V OC ) below 0.29 V, and, for coaxial devices, large leakage currents >1 pA. Furthermore, to accurately identify potentially unique absorption modes through photocurrent spectra ...

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mentioning

confidence: 99%

Coaxial multishell nanowires with high-quality electronic interfaces and tunable optical cavities for ultrathin photovoltaics

Kempa

Cahoon

Kim

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

198

219

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“…[1][2][3][4][5][6] The photovoltages of Si microwire arrays are not yet comparable, however, to the highest values observed from planar crystalline Si photovoltaics. By analogy to planar Si systems, one approach to improve the photovoltage of the Si microwire arrays would be to operate the system under highlevel injection conditions.…”

Section: Introductionmentioning

confidence: 95%

Operation of lightly doped Si microwires under high-level injection conditions

Santori

Strandwitz

Grimm

et al. 2014

Energy Environ. Sci.

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The operation of lightly doped Si microwire arrays under high-level injection conditions was investigated by measurement of the current-potential behavior and carrier-collection efficiency of the wires in contact with non-aqueous electrolytes, and through complementary device physics simulations. The currentpotential behavior of the lightly doped Si wire array photoelectrodes was dictated by both the radial contact and the carrier-selective back contact. For example, the Si microwire arrays exhibited n-type behavior when grown on a n + -doped substrate and placed in contact with the 1,1 0 -dimethylferrocene +/0 -CH 3 OH redox system. The microwire arrays exhibited p-type behavior when grown on a p + -doped substrate and measured in contact with a redox system with a sufficiently negative Nernstian potential. The wire array photoelectrodes exhibited internal quantum yields of $0.8, deviating from unity for these radial devices. Device physics simulations of lightly doped n-Si wires in radial contact with the 1,1 0 -dimethylferrocene-CH 3 OH redox system showed that the carriercollection efficiency should be a strong function of the wire diameter and the carrier lifetime within the wire. Small diameter (d < 200 nm) wires exhibited low quantum yields for carrier collection, due to the strong inversion of the wires throughout the wire volume. In contrast, larger diameter wires (d > 400 nm) exhibited higher carrier collection efficiencies that were strongly dependent on the carrier lifetime in the wire, and wires with carrier lifetimes exceeding 5 ms were predicted to have near-unity quantum yields. The simulations and experimental measurements collectively indicated that the Si microwires possessed carrier lifetimes greater than 1 ms, and showed that radial structures with micron dimensions and high material quality can result in excellent device performance with lightly doped, structured semiconductors. Broader contextStructuring semiconductors on the nano-and microscale is a promising route to enable exible, lightweight photovoltaics and efficient solar fuels devices. Wire devices with radial junctions should allow for both the efficient absorption of light along the axial dimension of the wire and radial collection of excited photocarriers, therefore enabling the fabrication of efficient devices based on inexpensive materials with low electronic quality. Prior systematic experimental and device physics modeling has largely focused on arrays of doped semiconductors, including Si radial p-n junction devices. The work described herein focuses on the device performance and device physics of lightly doped Si microwires, to allow for new device architectures and increased understanding of devices using other semiconductor materials with less controllable doping.

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“…Silicon nanowires (Si-NWs) have many unique properties which are a perspective for further applications in the production of optoelectronic devices such as sensors, solar cells, transistors and so on [1,2]. Although they were synthesized by many methods and some of them give satisfactory results, their application for photovoltaic devices are still ineffective.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Si-NWs by PECVD using Sn as catalyst on TCO thin film for optoelectronic devicies

Pham

et al. 2014

Adv. Nat. Sci: Nanosci. Nanotechnol.

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In this paper we focus on silicon nanowires (Si-NWs) which were fabricated on transparent conductive substrates by plasma-enhanced chemical vapor deposition (PECVD) method using Sn as stimulated catalyst metal. Transparent conductive substrates which we used are ZnO fabricated by direct current (dc) sputtering. Property of ZnO thin film was investigated by x-ray diffraction (XRD), volt-ohm-miliampere (VOM) meter, and Stylus method. In order to grow Si-NWs using PECVD we need to use metal as catalyst. We used Sn as catalyst to synthesize Si-NWs. Sn catalyst nanoparticles were fabricated by high vacuum evaporation system (SenVact). Size and density of Sn catalyst nanoparticles were investigated by scanning electron microscope (SEM). The influence of the thickness of metal layers on forming Sn catalyst nanoparticles was studied. In particular, the factors affecting the formation of Si-NWs such as temperature and rate of gas were examined. Si-NWs’ properties were investigated by SEM, Raman spectroscopy and energy dispersive x-ray (EDX) spectrocopy.

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Radial junction silicon wire array solar cells fabricated by gold-catalyzed vapor-liquid-solid growth

Cited by 82 publications

References 25 publications

Coaxial multishell nanowires with high-quality electronic interfaces and tunable optical cavities for ultrathin photovoltaics

Coaxial multishell nanowires with high-quality electronic interfaces and tunable optical cavities for ultrathin photovoltaics

Operation of lightly doped Si microwires under high-level injection conditions

Synthesis of Si-NWs by PECVD using Sn as catalyst on TCO thin film for optoelectronic devicies

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