Structural, optical and electrical characterization of nanostructured porous silicon: Effect of current density

Kulathuraan, K.; Mohanraj, K.; Natarajan, B.

doi:10.1016/j.saa.2015.07.055

Cited by 23 publications

(14 citation statements)

References 31 publications

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“…One can note that SiNWs fabrication with good uniformity/reproducibility are a MACE feature [4,34]. It is worth noting that the observed rectifying behaviour of these SiNWs is similarly shown in the literature for porous silicon [42,[46][47][48]. Importantly, the nonlinear I-V characteristics and the rectifying event are mainly controlled by the SiNW layers and ascribed to Ag/SiNWs:p-Si since the Si/Al interface was proved to be ohmic [47,48].…”

Section: I-v Measurementssupporting

confidence: 66%

“…This is confirmed by the reduction of SiNWs amount as seen above in the SEM images and more precisely by the reduction of the volume filling ratio over etching time. These latter indicate that the monotonous decrease of the PL intensity over etching duration is interpreted as restriction and diminution of excitation volume which in turn is proportional to the amount of effective light-emitting crystallites [17,41,42].…”

Section: Photoluminescence Spectroscopymentioning

confidence: 95%

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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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Section: I-v Measurementssupporting

confidence: 66%

Section: Photoluminescence Spectroscopymentioning

confidence: 95%

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

et al. 2020

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“…10, b). The typical times of direct and reverse current setting at pulse shift were respectively 40 and 13 s. This indicates a presence of slow traps [11,12]. As can be seen in fig.…”

Section: Porous Silicon Surface Morphologymentioning

confidence: 74%

Investigation of Porous Silicon Photoconductive Structures

Monastyrskii¹

2018

ELIT-2018

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Porous silicon layers photoconductive and electrical properties obtained by electrochemical etching of silicon have been investigated. Photoconductive and currentvoltage properties depend on structure morphology are determined by not only properties of modified layer, but presence of charge carriers' traps. The photosensitivity of structures with PS layers is determined by thickness of porous layer.

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“…The PSi substrate allows the possibility to develop optical and electrochemical devices through the covalent immobilization of either organic or inorganic compounds, which affords a more stable sensor device [1][2][3]. One advantage of this material is its large surface area, which allows the immobilization of large quantities of nanoparticles, organic molecules, and (bio) macromolecules with capacity to perform electron transfer reactions on its surface [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Porous Silicon Nanostructured Materials for Sensing Applications: Molecular Assembling and Electrochemical or Optical Evaluation

et al. 2016

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Porous silicon (PSi) combines the potential of miniaturization with a very large surface area. The PSi surface can be chemically modified resulting in a high sensitivity (low detection threshold) device for chemical and biomolecular sensing. In previous work, we have shown that redox proteins and fluorescent ligands can be infiltrated into PSi (PSiMc) structures. The hybrid devices have shown interesting new properties produced by the coupling of the individual properties of PSi nanostructures and the modifiers. In this work, we have obtained a PSiMc/redox protein bioelectrode, which presents a quasi-reversible electrochemical response. This effect was attributed to the semiconducting nature of the PSi substrate and to the functional groups of the crosslinking molecules (MPTS), which together produce a capacitive effect on the device. On the other hand, the chemical modification of PSiMc with fluorescent ligands allowed us to fabricate fluorescent PSi hybrid nanostructures, which were tested for the detection of environmental pollutants such as heavy metals (specifically Hg 2+ ). We found that the selectivity of this optical device depends on the selected recognizing molecule. The captured metal induces the formation of a metallic complex that shows higher fluorescence compared with the sensor device. These results demonstrate the viability of using porous silicon as optical sensors and electrochemical biosensors. The infiltration of fluorescent recognizing molecules and proteins into the PSi matrix were evaluated by specular reflectance, FTIR spectroscopy, fluorescence spectroscopy and cyclic voltammetry.

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Structural, optical and electrical characterization of nanostructured porous silicon: Effect of current density

Cited by 23 publications

References 31 publications

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

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

Investigation of Porous Silicon Photoconductive Structures

Porous Silicon Nanostructured Materials for Sensing Applications: Molecular Assembling and Electrochemical or Optical Evaluation

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