PHOTOSENSITIVE MATRIX BASED ON POROUS MICROCRYSTALLINE SILICON

The article presents the results of experimental researches of optoelectric properties of porous silicon. Layers of porous silicon were formed using electrochemical etching process in water-alcohol solutions of hydrofluoric acid on plates with a pre-established microrelief surface. Evaluation of possibility of using of created structure as the artificial retina component was performed based on the results of the research.

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Photoluminescence in Porous Silicon: Evidence for the Quantum Confinement Model

MRS Proceedings ◽

10.1557/proc-256-111 ◽

1991 ◽

Vol 256 ◽

Cited By ~ 4

Author(s):

David L. Naylor ◽

Sung B. Lee ◽

John C. Pincenti ◽

Brett E. Bouma

Keyword(s):

Porous Silicon ◽

Hydrofluoric Acid ◽

Quantum Wire ◽

Quantum Confinement ◽

Electrochemical Etching ◽

Photoluminescence Spectra ◽

Peak Wavelength ◽

Effects Of Temperature ◽

Good Agreement ◽

Confinement Model

ABSTRACTPhotoluminescence spectra have been measured in porous silicon following electrochemical etching in dilute hydrofluoric acid (HF). The effects of HF concentration during etching on the efficiency and peak wavelength of photoluminescence have been investigated. The effects of temperature between 25°C and 200°C on PL spectra have been recorded. Photoluminescence lifetimes as a function of wavelength have been studied following ultrashort UV photoexcitation. A number of lifetime components in the decay are observed the longest in good agreement over the wavelength range of 500 to 600 nm with a silicon quantum wire model. At longer wavelengths a departure from lifetimes of the wire model is observed and two hypotheses for the discrepancy are presented.

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Study of Composite Structures Based on a Porous Silicon Matrix and Nanoparticles Ag/Zno Used as Non-Invasive Highly Sensitive Biosensor Devices

Composite Materials ◽

10.5772/intechopen.92850 ◽

2021 ◽

Author(s):

Veniamin Koshevoi ◽

Anton Belorus ◽

Ilya Pleshanov ◽

Anton Timchenko ◽

Roman Denisenko ◽

...

Keyword(s):

Porous Silicon ◽

Hydrofluoric Acid ◽

Emission Spectroscopy ◽

Composite Structures ◽

Electrochemical Etching ◽

Silicon Matrix ◽

Non Invasive ◽

Highly Sensitive ◽

Porous Matrices ◽

Scanning Electron

In this work composite structures based on a porous silicon were obtained and studied. Porous matrices were formed by electrochemical etching in aqueous solutions of hydrofluoric acid. Based on the obtained substrates, por-silicon (Si)/silver (Ag) and por-Si/zinc oxide (ZnO) composite structures were formed. These composites were functionalized by various methods (electro (E)-, thermo (T)-, electrothermal exposure) as a result of which the structures were modified. When studying the samples by scanning electron microscopy (SEM), it was concluded that silver nanoparticles actively diffused into the pores under these technological modes of functionalization. The por-Si/Ag and por-Si/ZnO composite structures were also studied using the following methods: infrared (IR) spectroscopy and Raman ultrasoft X-ray emission spectroscopy. Also, the photoluminescent characteristics of the samples were studied. Based on the obtained results, it was concluded that functionalization methods actively change the phase composition of structures and the optical properties of composites.

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POROUS SILICON: INFLUENCE OF ETCHING TEMPERATURE ON MICROSTRUCTURE AND LUMINESCENCE

Surface Review and Letters ◽

10.1142/s0218625x0100118x ◽

2001 ◽

Vol 08 (05) ◽

pp. 429-433 ◽

Cited By ~ 3

Author(s):

D. J. BLACKWOOD ◽

Y. ZHANG

Keyword(s):

Porous Silicon ◽

Light Source ◽

Hydrofluoric Acid ◽

Uv Light ◽

Electrochemical Etching ◽

Light Emitting ◽

Influence Of Temperature ◽

Etching Solution ◽

Experimental Parameters

Electrochemical etching in solutions based on hydrofluoric acid has been widely used to form light-emitting porous silicon. However, the effects of a number of the experimental parameters on the quality of the porous silicon produced have yet to be fully investigated. In the present paper the influence of temperature and viscosity of the etching solution is evaluated in terms of the morphology and porosity of the porous silicon produced as well as the wavelength of the photoluminescence or electroluminescence subsequently emitted. It was found that under stimulation from a UV light source the wavelength of the photoluminescence emitted from the porous silicon films blueshifted with decreasing etching temperature. SEM and AFM investigations revealed that this blueshifting of the photoluminescence resulted from the production of smaller nanocrystals at the lower etching temperatures.

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In Situ Growth of ZnO inside a Porous Silicon Matrix Obtained by Electrochemical Etching with a Hydrofluoric Acid-Formaldehyde Solution

Journal of Nanomaterials ◽

10.1155/2019/9863145 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

R. Juárez-Nahuatlato ◽

G. García ◽

M. Pacio ◽

Roberto Portillo ◽

N. Perez-Amaro ◽

...

Keyword(s):

Porous Silicon ◽

Hydrofluoric Acid ◽

Electrochemical Etching ◽

Nitrogen Adsorption ◽

Ultraviolet Region ◽

Ultraviolet Emission ◽

Silicon Matrix ◽

Electrolytic Process ◽

Band Emission ◽

Before And After

We present zinc oxide (ZnO) particles obtained inside a porous silicon matrix in the same electrolytic process using a p-type silicon wafer in a hydrofluoric acid (HF) solution containing formaldehyde (CH2O) and hydrated zinc sulfate as additives. The X-ray diffraction pattern of the sample confirmed the presence of ZnO with a hexagonal-type wurtzite structure. Photoluminescence (PL) spectra of the samples, before and after the functionalization process, were measured to observe the effect of ZnO inside the porous silicon. The PL measurements of porous silicon functionalized with ZnO (ZnO/PS) revealed infrared, red, blue, and ultraviolet emission bands. The ultraviolet region corresponds to the band-band emission of ZnO, and the visible emission is attributed to defects. The results of the nitrogen adsorption/desorption isotherms of the PS and ZnO/PS samples revealed larger BET surface areas and pore diameters for the ZnO/PS sample. We conclude that ZnO/PS can be obtained in a one-step electrolytic process. These types of samples can be used in gas sensors and photocatalysis.

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Raman Scattering in Electrochemically Prepared Porous Silicon

MRS Proceedings ◽

10.1557/proc-256-69 ◽

1991 ◽

Vol 256 ◽

Cited By ~ 3

Author(s):

Y. -J. Wu ◽

X. -S. Zhao ◽

P. D. Persans

Keyword(s):

Porous Silicon ◽

Raman Scattering ◽

Amorphous Silicon ◽

Room Temperature ◽

High Efficiency ◽

Silicon Oxide ◽

Electrochemical Etching ◽

Visible Range ◽

Microcrystalline Silicon ◽

Hydrogenated Amorphous

ABSTRACTPorous silicon of various porosity has been prepared by electrochemical etching of silicon with different doping levels. Room temperature photoluminescence in the visible range is observed from the powder scraped from the top layer of the etched samples. In this paper we use Raman scattering to characterize the source of the high efficiency photoluminescence. We have also studied microcrystalline silicon prepared by thermal annealing of hydrogenated amorphous silicon/amorphous silicon oxide multilayers.

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Quantum Confinement of Integrated Pulse Electrochemical Etching of Porous Silicon for Metal Semiconductor Metal Photodetector

Materials Science Forum ◽

10.4028/www.scientific.net/msf.846.245 ◽

2016 ◽

Vol 846 ◽

pp. 245-255 ◽

Cited By ~ 1

Author(s):

Alhan Farhanah Abd Rahim ◽

Mohamad Syarizal Abdullah ◽

Ainorkhilah Mahmood ◽

Nihad K. Ali ◽

Musa Mohamed Zahidi

Keyword(s):

Porous Silicon ◽

Delay Time ◽

Quantum Confinement ◽

Electrochemical Etching ◽

Quantum Confinement Effect ◽

Blue Shift ◽

Pulse Method ◽

Etching Process ◽

Metal Semiconductor Metal ◽

Msm Photodetector

Porous silicon (PS) was successfully synthesized via novel integrated pulsed electrochemical etching of an n-type (100) silicon (Si) substrate under various condition. The PS was etched using hydrofluoric acid (HF) based solution and the porosity was optimized by introducing electroless chemical etching process prior to photo electrochemical (PEC) anodization. In the electroless etching, a delay time (TD) of 2 min was applied. After that a cycle time (T) and pause time () of pulsed current were supplied throughout the 30 min PEC etching process. As grown Si and PS through conventional direct current (DC) anodization were also included for comparison. The result obtained showed that applying delay time helps to improve the uniformity and density of the porous structures. AFM indicated that the roughness of the Si increases as the dissolution of the Si occurred. Raman spectroscopy showed that an improvement in the crystalline quality of PS under pulse etching method compared to DC method indicated by the reduction of full width at half maximum (FWHM). A broad visible photoluminescence (PL) was observed from green to red with blue shift as nanocrystallite size decreases which constituted quantum confinement effect from the PS structures. Nickel (Ni) finger contact was deposited onto the PS to form metal semiconductor metal (MSM) photodetector. Ni/PS MSM photodetector by pulse method exhibited higher gain (2 times) compared to conventional Si device at 5 V bias.

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