Synthesis and Photoelectrochemical Study of Vertically Aligned Silicon Nanowire Arrays

Yuan, Guangbi; Zhao, Huaizhou; Liu, Xiaohua; Hasanali, Zainul; Zou, Yan; Levine, Andrew; Wang, Dunwei

doi:10.1002/ange.200902861

Cited by 30 publications

(27 citation statements)

References 39 publications

(36 reference statements)

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“…Firstly, in the low-frequency region, the impedance is approximately 10 times lower than that of EE SiNWs, despite the fact that extra caution was taken to passivate the surface of the supporting substrate by using Al 2 O 3 (see the Experimental Section). [23] Secondly, although the general trend that j Z j decreases as f increases is followed, it significantly deviates from j Z j / 1/f (Figure 4 a). This result suggests that charge-transfer channels other than that through the space-charge region and the surface states exist; these channels seriously undermine the capacitive nature of the space-charge region.…”

mentioning

confidence: 84%

“…All reagents were used as received without further purification except Me 2 Fc + BF 4 À , which was synthesized in-house. [23] For all data reported here, simulated sunlight (100 mW cm À2 , AM 1.5, Oriel 96000) was used as the light source. The current density versus potential (J-V) measurements were conducted at a scan rate of 10 mV s À1 .…”

Section: Methodsmentioning

confidence: 99%

“…Chemically grown SiNWs were synthesized by a method previously reported by us. [23] The growth was carried out in a homebuilt chemical vapor deposition apparatus with automatic flow and pressure controls. Doping was accomplished and controlled by varying the SiH 4 /PH 3 ratio during the synthesis.…”

Section: Methodsmentioning

confidence: 99%

“…Note that by varying the doping levels, better performance on chemically grown SiNWs was measured (h = 0.35 %, doping level: 10 18 cm À3 ), [23] the performance nonetheless being on the same order of magnitude. To afford a more meaningful comparison, SiNWs of similar doping levels are compared herein, as shown in Figure 1.…”

mentioning

confidence: 99%

“…We compared three types of samples: planar Si wafers, SiNWs prepared by electroless etching, [13,[20][21][22] and SiNWs synthesized by a bottom-up chemical method. [23] Derived from planar Si crystals, electroless etched (EE) SiNWs have the same crystallography and doping level as Si crystals from the bulk, they differ only in the surface-to-volume ratio. Studying EE SiNWs allows the collection of quantitative information on their performance and to relate this information to the nanowire morphology.…”

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confidence: 99%

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Understanding the Origin of the Low Performance of Chemically Grown Silicon Nanowires for Solar Energy Conversion

et al. 2011

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Silicon nanowires (SiNWs) have been proposed as promising candidates for efficient solar energy conversion for at least three reasons: 1) the abundance of elemental Si and the rich knowledge of its electronic and photoelectronic properties, 2) the appeal of the nanowire morphology for improved charge collection, and 3) the widely available synthetic methods that can produce vertically aligned or randomly oriented high-quality SiNWs. [1][2][3][4][5] Despite intense efforts, however, the performance of SiNW-based solar cells remains significantly lower than what has been achieved for bulk Si or micrometer-scale wires. [6][7][8][9][10][11][12][13][14][15] The gap between the predicted performance and the inability to deliver raises an important question with regard to the origin of this problem. Owing to the similarity between the science of SiNWs and that of nanowires of many other compositions, finding answers to this question is of great importance to using these materials for efficient solar energy harvesting. [2,5] We performed a detailed study of SiNW electronic properties, which is aimed at understanding what limits the performance of SiNWs, by using electrochemical techniques. Our results reveal that the poor performance is not a result of the nanowire morphology, but is intrinsic to the growth chemistry. The finding suggests that more attention should be paid to the optimization of the synthesis of SiNWs in order to actualize the full potential of this exciting material for energy conversion purposes.Previous studies have shown that the high surface-tovolume ratio exhibited by SiNWs may be deleterious in reducing open circuit voltages. [1,16] This disadvantage can be partially compensated by gains in short-circuit current caused by the relaxation of charge diffusion distance requirements and improved light absorption; [1,7,14,[17][18][19] energy conversion efficiencies similar to that of bulk-Si-based devices are predicted. However, experimental efforts have failed to meet the expectation (Table 1), thus leaving important questions unanswered, such as whether the nanowire morphology is intrinsically disadvantaged and where research should be focused on.The first question we seek to answer experimentally is whether the nanowire morphology is intrinsically disadvantageous. We compared three types of samples: planar Si wafers, SiNWs prepared by electroless etching, [13,[20][21][22] and SiNWs synthesized by a bottom-up chemical method.[23] Derived from planar Si crystals, electroless etched (EE) SiNWs have the same crystallography and doping level as Si crystals from the bulk, they differ only in the surface-to-volume ratio. Studying EE SiNWs allows the collection of quantitative information on their performance and to relate this information to the nanowire morphology. An efficiency of 12.8 % (V oc : 563 mV; J sc : 33.5 mA cm À2 ; fill factor (FF): 68.0 %) was measured on planar Si with a doping level of 10 15 cm À3 , [24] which is in consistency with literature reports. [16,25,26] A slightly lower efficiency,...

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confidence: 84%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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Understanding the Origin of the Low Performance of Chemically Grown Silicon Nanowires for Solar Energy Conversion

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Silicon for Thermoelectric Energy Harvesting Applications

Narducci

Belsito

Morata

2017

Advanced Micro and Nanosystems

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Silicon Nanowires for Biosensing, Energy Storage, and Conversion

et al. 2013

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Semiconducting silicon nanowires (SiNWs) represent one of the most interesting research directions in nanoscience and nanotechnology, with capabilities of realizing structural and functional complexity through rational design and synthesis. The exquisite control of chemical composition, structure, morphology, doping, and assembly of SiNWs, in both individual and array format, as well as incorporation with other materials, offers a nanoscale building block with unique electronic, optoelectronic, and catalytic properties, thus allowing for a variety of exciting opportunities in the fields of life sciences and renewable energy. This review provides a brief summary of SiNW research in the past decade, from the SiNW synthesis by both the top-down approaches and the bottom-up approaches, to several important biological and energy applications including biomolecule sensing, interfacing with cells and tissues, lithium-ion batteries, solar cells, and photoelectrochemical conversion.

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Synthesis and Photoelectrochemical Study of Vertically Aligned Silicon Nanowire Arrays

Cited by 30 publications

References 39 publications

Understanding the Origin of the Low Performance of Chemically Grown Silicon Nanowires for Solar Energy Conversion

Understanding the Origin of the Low Performance of Chemically Grown Silicon Nanowires for Solar Energy Conversion

Silicon for Thermoelectric Energy Harvesting Applications

Silicon Nanowires for Biosensing, Energy Storage, and Conversion

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