Investigation on the Photoluminescence of p-Type Porous Silicon for Ultraviolet Detector

The promotion of silicon (Si) from being the key material for microelectronics to an interesting material for optoelectronic application is a consequence of the possibility to reduce its device dimensionally by a cheap and easy technique. In fact, electrochemical etching of Si under controlled conditions leads to the formation of nanocrystalline porous silicon (PS) where quantum confinement of photo excited carriers and surface species yield to a band gap opening and an increased radiative transition rate resulting in efficient light emission. In the present study, the nanostructured PS samples were prepared using anodic etching of p-type silicon. The effect of current density on structural and optical properties of PS, has been investigated. XRD studies confirm the presence of silicon nanocrystallites in the PS structure. By increasing the current density, the average estimated values of grain size are found to be decreased. SEM images indicate that the pores are surrounded by a thick columnar network of silicon walls. The observed PL spectra at room temperature for all the current densities confirm the formation of PS structures with nanocrystalline features. PL studies reveal that there is a prominent visible emission peak at 606 nm. The obtained variation of intensity in PL emission may be used for intensity varied light emitting diode applications. These studies confirm that the PS is a versatile material with potential for optoelectronics application.

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Optical Studies of porous Silicon

MRS Proceedings ◽

10.1557/proc-298-379 ◽

1993 ◽

Vol 298 ◽

Cited By ~ 1

Author(s):

T. Lin ◽

M. E. Sixta ◽

J. N. Cox ◽

M. E. Delaney

Keyword(s):

Optical Properties ◽

Fourier Transform ◽

Steady State ◽

Porous Silicon ◽

Ftir Spectroscopy ◽

Optical Studies ◽

Etched Silicon ◽

Bending Modes ◽

P Type ◽

Over Time

AbstractThe optical properties of both electrochemically anodized and chemically stain-etched porous silicon are presented. Fourier transform infrared (FTIR) spectroscopy showed that absorbance in stain-etched samples was 3x and 1.7x greater than in anodized samples for the SiH/SiH2 stretch and scissors-bending modes, respectively. Also, oxygen is detected in stain-etched samples immediately after formation, unlike anodized samples. Photoluminescence measurements showed different steady state characteristics. Electrochemical-etched silicon samples stored in air increased in photoluminescent intensity over time, unlike the stain-etched samples. A photoluminescent device made by anodization on epitaxial p-type material (0.4 Ωm) on n-type substrate (0.1 Ω-cm) did not exhibit electroluminescence.

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Gold nanoclusters reductively deposited on porous silicon: morphology and electronic structures

Canadian Journal of Chemistry ◽

10.1139/v98-146 ◽

1998 ◽

Vol 76 (11) ◽

pp. 1707-1716 ◽

Cited By ~ 30

Author(s):

I Coulthard ◽

S Degen ◽

Y -J Zhu ◽

T K Sham

Keyword(s):

Gold Nanoparticles ◽

Porous Silicon ◽

Photoelectron Spectroscopy ◽

Gold Nanoclusters ◽

Gold Complex ◽

X Ray Diffraction ◽

Complex Ions ◽

X Ray ◽

Preparation Conditions ◽

P Type

Utilizing porous silicon as a reducing agent and a substrate, gold complex ions [AuCl4]- were reduced from aqueous solution to produce nanoparticles of gold upon the surface of porous silicon. Scanning electron microscopy (SEM) was utilized to study the morphology of the porous silicon layers and the deposits of gold nanoparticles. It is found that preparation conditions have a profound effect on the morphology of the deposits, especially on porous silicon prepared from a p-type wafer. The gold nanoparticles, varying from micrometric aggregates of clusters of the order of 10 nm, to a distribution of nearly spherical clusters of the order of 10 nm, to strings of ~10 nm were observed and compared to bulk gold metal using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). These techniques confirm and complement the SEM findings. The potential for this reductive deposition technique is noted.Key words: gold nanostructures, reductive deposition, porous silicon, morphology, X-ray spectroscopy.

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Photovoltaic Characterization of Trapping in Porous Silicon

MRS Proceedings ◽

10.1557/proc-358-587 ◽

1994 ◽

Vol 358 ◽

Cited By ~ 1

Author(s):

D. W. Boeringer ◽

R. Tsu

Keyword(s):

Porous Silicon ◽

Photovoltaic Effect ◽

Light Spot ◽

Dangling Bond ◽

Photogenerated Electrons ◽

Device Applications ◽

Photovoltaic Characterization ◽

P Type ◽

Silicon Based ◽

Position Sensitive Detectors

ABSTRACTWe report the first observation of the lateral photovoltaic effect in porous silicon. Contacts placed on either side of a porous silicon region develop a voltage up to several millivolts if the sample is asymmetrically illuminated. If the light spot is closer to one contact, the voltage will have one polarity; if it is closer to the other contact, the polarity will be opposite. In the case of n-type, the contact nearest the light spot is positive; for p-type, the contact nearest the light spot is negative In the region between the contacts, the photovoltage varies almost linearly with the position of the light spot, over a distance 4.5 cm across. The origin of our lateral photoeffect may be explained by the trapping of photoexcited carriers by a pair of dangling bond centers in porous silicon. In the case of p-type, the photogenerated electrons are trapped by the dangling bond states while holes diffuse away in the substrate. The situation for n-type is opposite; holes are trapped by the dangling bond states while electrons diffuse away in the substrate. This differs from the conventional lateral photoeffect, which arises under the nonuniform illumination of a junction between two layers of differing conductivities. Hamamatsu sells silicon-based position-sensitive detectors with a resolution down to 0.1 µm. The possibility of using this lateral photoeffect to characterize these dangling bond states in porous silicon as well as several possible device applications will be discussed.

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Electroluminescence and Photoluminescence Properties of Porous Silicon Nanostructures with Optimum Current Density of Photo-Electrochemical Anodisation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.667.180 ◽

2013 ◽

Vol 667 ◽

pp. 180-185

Author(s):

M. Ain Zubaidah ◽

F.S. Husairi ◽

S.F.M. Yusop ◽

Noor Asli Asnida ◽

Mohamad Rusop ◽

...

Keyword(s):

Porous Silicon ◽

Volume Ratio ◽

Boron Doping ◽

Peak Position ◽

Silicon Nanostructures ◽

Etching Time ◽

Photoluminescence Properties ◽

Current Densities ◽

Pl Spectrum ◽

P Type

P-type silicon wafer ( orientation; boron doping; 0.75 ~ 10 Ω cm-1) was used to prepare samples of porous silicon nanostructures (PSiNs). All samples have been prepared by using photo-electrochemical anodisation. A fixed etching time of 30 minutes and volume ratio of electrolyte, hydrofluoric acid 48% (HF48%) and absolute ethanol (C2H5OH), 1:1 were used for various current densities, J. There were sample A (J=10 mA/cm2), sample B (J=20 mA/cm2), sample C (J=30 mA/cm2), sample D (J=40 mA/cm2) and sample E (J=50 mA/cm2). Photoluminescence (PL) and electroluminescence (EL) spectra were investigated. Maximum peak position of PL spectrum at about ~675 nm, while the maximum EL spectrum at about ~650 nm (which is similar to the PL spectrum).

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