Structural and optical properties of silicon nanowires synthesized by Ag-assisted chemical etching

Lajvardi, M.; Eshghi, Hosein; Ghazi, M. E.; Izadifard, Morteza; Goodarzi, A.

doi:10.1016/j.mssp.2015.07.032

Cited by 49 publications

(27 citation statements)

References 29 publications

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“…1(a,b)). A similar texture has also been reported in a previous study23. The formation of open cell-like structures is associated with the etching time and etchant concentration39.…”

Section: Resultssupporting

confidence: 85%

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Surface Characteristics of Silicon Nanowires/Nanowalls Subjected to Octadecyltrichlorosilane Deposition and n-octadecane Coating

Yilbaş

Salhi

Yousaf

et al. 2016

Sci Rep

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In this study, nanowires/nanowalls were generated on a silicon wafer through a chemical etching method. Octadecyltrichlorosilane (OTS) was deposited onto the nanowire/nanowall surfaces to alter their hydrophobicity. The hydrophobic characteristics of the surfaces were further modified via a 1.5-μm-thick layer of n-octadecane coating on the OTS-deposited surface. The hydrophobic characteristics of the resulting surfaces were assessed using the sessile water droplet method. Scratch and ultraviolet (UV)-visible reflectivity tests were conducted to measure the friction coefficient and reflectivity of the surfaces. The nanowires formed were normal to the surface and uniformly extended 10.5 μm to the wafer surface. The OTS coating enhanced the hydrophobic state of the surface, and the water contact angle increased from 27° to 165°. The n-octadecane coating formed on the OTS-deposited nanowires/nanowalls altered the hydrophobic state of the surface. This study provides the first demonstration that the surface wetting characteristics change from hydrophobic to hydrophilic after melting of the n-octadecane coating. In addition, this change is reversible; i.e., the hydrophilic surface becomes hydrophobic after the n-octadecane coating solidifies at the surface, and the process again occurs in the opposite direction after the n-octadecane coating melts.

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“…1(a,b)). A similar texture has also been reported in a previous study23. The formation of open cell-like structures is associated with the etching time and etchant concentration39.…”

Section: Resultssupporting

confidence: 85%

“…In addition, the yield stress of rough wires with a certain cross-sectional size depends on the surface notch depth. Lajvardi et al 23. have investigated silicon nanowires synthesized via silver-assisted chemical etching.…”

mentioning

confidence: 99%

Surface Characteristics of Silicon Nanowires/Nanowalls Subjected to Octadecyltrichlorosilane Deposition and n-octadecane Coating

Yilbaş

Salhi

Yousaf

et al. 2016

Sci Rep

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“…where E is PL peak position (eV), Eg is the band gap of c-Si ( To explain the origin of this PL emission, several mechanisms have been proposed including the quantum confinement (QC) effects and the presence of defects in an SiO x /Si interface and/or in the surface of the oxide related to the Si-O-Si bonds [36,37]. However, the QC effects, which enhance the radiative recombination of excitons, remain the most approved model which dictates that the crystallite Si size should be less than the Bohr radius of the free exciton of bulk silicon [17]. In the present work, the SiNW diameters are within one hundred to a very few hundred of nanometers, these values are much larger than the Bohr radius of excitons (5 nm) present in Si crystals.…”

Section: Photoluminescence Spectroscopymentioning

confidence: 99%

“…Based upon the bottom-up and top down approaches, numerous methods have been used to fabricate SiNWs such as vapor-liquid-solid, thermal evaporation, molecular beam epitaxy, laser ablation, and lithography [12][13][14][15][16]. However, these techniques have some limitations as they generally require expensive and complex equipment, employ hazardous silicon precursors, and involve high vacuum and high temperature [17]. These features make the synthesis expensive and…”

Section: Introductionmentioning

confidence: 99%

Elucidating the Effect of Etching Time Key-Parameter toward Optically and Electrically-Active Silicon Nanowires

et al. 2020

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In this work, vertically aligned silicon nanowires (SiNWs) with relatively high crystallinity have been fabricated through a facile, reliable, and cost-effective metal assisted chemical etching method. After introducing an itemized elucidation of the fabrication process, the effect of varying etching time on morphological, structural, optical, and electrical properties of SiNWs was analysed. The NWs length increased with increasing etching time, whereas the wires filling ratio decreased. The broadband photoluminescence (PL) emission was originated from self-generated silicon nanocrystallites (SiNCs) and their size were derived through an analytical model. FTIR spectroscopy confirms that the PL deterioration for extended time is owing to the restriction of excitation volume and therefore reduction of effective light-emitting crystallites. These SiNWs are very effective in reducing the reflectance to 9-15% in comparison with Si wafer. I-V characteristics revealed that the rectifying behaviour and the diode parameters calculated from conventional thermionic emission and Cheung's model depend on the geometry of SiNWs. We deduce that judicious control of etching time or otherwise SiNWs' length is the key to ensure better optical and electrical properties of SiNWs. Our findings demonstrate that shorter SiNWs are much more optically and electrically active which is auspicious for the use in optoelectronic devices and solar cells applications.Nanomaterials 2020, 10, 404 2 of 18 time-consuming and therefore hindered their applications for commercialized products. In contrast, an effective and promising synthetic method namely metal assisted chemical etching (MACE) has been proposed [2,4,[18][19][20]. This technique is simple, rapid, low cost, and suitable for both industrial and laboratory scales. Moreover, MACE allows to obtain high crystalline SiNWs quality, as well as an easy control of the different parameters including orientation, doping type, length, and diameter.The MACE method basically consists of two procedures, the formation of metal catalysts and the subsequent etching process which can be implemented either in a single step (1-MACE) [10,21] or in two steps (2-MACE) [17-20]. Moreover, the formation method, etching time, etching temperature, metal deposition time, and lastly the etchants' concentrations have a crucial influence on the morphology of SiNWs [2,5,17]. Ghosh et al. reported that SiNWs grown by MACE are usually covered with silicon nanocrystals due to the side wall etching and which are the origin of quantum confinement (QC) effects owing to their small dimensions [20]. Recently, several research groups have succeeded in the synthesis of optically-active SiNWs exhibiting a significant PL emission and a very low reflectance [3,4,17]. On the other hand, Qi et al. have demonstrated the fabrication of electrically-active SiNWs through heavily doped SiNWs with rough surface where a high Schottky barrier exists at the interface of SiNWs and the metal [22]. Nevertheless, further investigation is required t...

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“…Optical properties of SiNWs are rather well understood. SiNWs arrays, fabricated by metal‐assisted chemical etching (MACE), exhibit ultra‐low reflectance in visible and infrared (IR) region as compared with bulk crystalline silicon (c‐Si), which decreases with nanowire length. This fact was explained by the light‐trapping effect caused by light scattering in SiNW array .…”

Section: Introductionmentioning

confidence: 99%

Optical Diagnostics of Free Charge Carriers in Silicon Nanowire Arrays

Rodichkina

Nychyporuk

Pavlikov

et al. 2020

Physica Status Solidi (a)

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The impact of free charge carriers in arrays of silicon nanowires (SiNWs) of p‐ and n‐type conductivities on their optical properties is probed by means of the infrared spectroscopy in attenuated total reflectance mode (IR‐ATR) and Raman scattering. SiNWs are fabricated by metal‐assisted chemical etching of low‐doped p‐type crystalline silicon (c‐Si) wafers followed by thermodiffusional doping with p‐ and n‐type impurities. The free charge carrier concentration in SiNWs is determined from their ATR spectra fitted using a model of the anisotropic effective medium with free charge carriers. The obtained data on the free charge carrier concentrations in the range of 1019–1020 cm−3 are compared with the corresponding values obtained from the Raman spectra, which are analyzed by considering the Fano effect in SiNWs, and the results of both methods are used to evaluate the electrical properties of SiNWs. The proposed optical methods to probe the electrical properties of SiNWs are discussed in view of possible applications in nanoelectronics and thermoelectric devices.

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Structural and optical properties of silicon nanowires synthesized by Ag-assisted chemical etching

Cited by 49 publications

References 29 publications

Surface Characteristics of Silicon Nanowires/Nanowalls Subjected to Octadecyltrichlorosilane Deposition and n-octadecane Coating

Surface Characteristics of Silicon Nanowires/Nanowalls Subjected to Octadecyltrichlorosilane Deposition and n-octadecane Coating

Elucidating the Effect of Etching Time Key-Parameter toward Optically and Electrically-Active Silicon Nanowires

Optical Diagnostics of Free Charge Carriers in Silicon Nanowire Arrays

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