Elaboration and Light Emission Properties of Low Doped p-Type Porous Silicon Microcavities

1996 ◽  
Vol 452 ◽  
Author(s):  
G. Lérondel ◽  
P. Ferrand ◽  
R. Romestain
Keyword(s):  
Porous Silicon ◽  
Near Infrared ◽  
Light Emission ◽  
Narrow Band ◽  
Bragg Reflectors ◽  
Strong Emission ◽  
Luminescence Efficiency ◽  
Fabry Perot ◽  
Current Densities ◽  
P Type

AbstractWe account for the elaboration of Bragg reflectors and microcavities based on efficiently luminescent porous silicon. A characterisation of very thin porous silicon layers obtained with current densities of formation varying from 1.5 mA to 300 mA is presented. The resulting refractive index variation (typically from 1.37 to 1.86 at 700 nm) enables the elaboration of high quality Bragg reflectors and Fabry-Perot filters from the yellow to the near infrared. Although low doped p-type porous silicon develops rougher interfaces than highly doped p-type porous silicon, its better luminescence efficiency has enabled us to elaborate microcavities with a strong emission in a narrow band.

Improved Interference Filter Structures Made of Porous Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
M. Thönissen ◽  
M. G. Berger ◽  
M. Krüger ◽  
W. Theiβ ◽  
S. Hilbrich ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Interference Filter ◽  
Refractive Indices ◽  
Bragg Reflectors ◽  
Continuous Change ◽  
Specific Design ◽  
Fabry Perot ◽  
Current Densities ◽  
Substrate Doping ◽  
Filter Structures

AbstractRecently passive optical devices like filter structures or waveguides based on porous silicon have attracted high interest due to their easy and cheap fabrication. We have formed interference filters using porous silicon by changing the current density during formation. For the specific design of these filter structures a calibration of the etch rate and the refractive indices is required. Therefore we have determined the effective dielectric function for different substrate doping levels and anodization current densities by fitting reflectance spectra. Based on these results different kinds of reflectance filters consisting of discrete layers (Bragg reflectors, Fabry-Perot filters) as well as filters with a continuous change of the refractive indices with depth (rugate-filters) can be realised. Furthermore we present applications of these filter structures such as anti-reflectance coatings and high quality mirrors.

Structural, Surface Morphological and Photoluminescence Properties of Nanostructured Porous Silicon Material for Optoelectronics Application

2012 ◽  
Vol 584 ◽  
pp. 290-294 ◽  
Author(s):  
Jeyaprakash Pandiarajan ◽  
Natarajan Jeyakumaran ◽  
Natarajan Prithivikumaran
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Light Emission ◽  
Electrochemical Etching ◽  
Light Emitting Diode ◽  
Radiative Transition ◽  
Sem Images ◽  
Optoelectronic Application ◽  
Gap Opening ◽  
P Type

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.

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

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).

Porous Silicon Morphology: Photo-Electrochemically Etched by Different Laser Wavelengths

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Shereen M. Faraj ◽  
Shaimaa M. Abd Al-Baqi ◽  
Nasreen R. Jber ◽  
Johnny Fisher
Keyword(s):  
Porous Silicon ◽  
Electrochemical Etching ◽  
Diode Lasers ◽  
Focus Of Attention ◽  
Blue Laser ◽  
Uniform Structure ◽  
Porous Layers ◽  
Current Densities ◽  
P Type ◽  
532 Nm

Porous silicon (PS) has become the focus of attention in upgrading silicon for optoelectronics. In this work, various structures were produced depending on the formation parameters by photo-electrochemical etching (PECE) process of n- and p-type silicon wafer at different time durations (5–90 mins) and different current densities (5, 15, and 20 mA/cm2) for each set of time durations. Diode lasers of 405 nm, 473 nm, and 532 nm wavelengths, each 50 mW power, were used to illuminate the surface of the samples during the etching process. The results showed that controlled porous layers were achieved by using blue laser, giving uniform structure which can make it possible to dispense with expensive methods of patterning the silicon.

ESR Study of Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
W. Y. Cheung ◽  
S. P. Wong ◽  
I. H. Wilson ◽  
C. F. Kan ◽  
S. K. Hark
Keyword(s):  
Porous Silicon ◽  
Spin Density ◽  
Light Emission ◽  
Blue Shift ◽  
Esr Spectra ◽  
Peak Position ◽  
Silicon Substrates ◽  
Post Annealing ◽  
G Value ◽  
P Type

ABSTRACTA detailed ESR study has been performed on porous silicon on both <100> and <111> p-type silicon substrates prepared using anodization in HF under a range of conditions and the results are correlated with the light emission properties. It is found that the ESR spectra are dependent upon the orientation of the samples. The ESR defect centers are identified to be the Pb centers or Pbo centers of the Si-SiO2 system from the g-value anisotropy maps. The variation of the spin density Ns with annealing conditions has also been studied for samples annealed either in nitrogen or oxygen ambient at 200°C for various time intervals. It is concluded that the increase or decrease of Ns are due to the generation or elimination of the Pb or Pbo centers in conjunction with the oxidation process during annealing. From PL study of these samples, it is found that there is no simple correlation between the spin density and the PL intensity. However, a blue shift in the PL peak position was observed both in samples after a post-annealing etch in HF solution, and in samples annealed in oxygen without a post-annealing etch. This blue shift supports the quantum confinement model of light emission from porous silicon.

Effect of Electrolyte Volume Ratio on Electroluminescence of Porous Silicon Nanostructures (PSiNs) Intensity

2013 ◽  
Vol 686 ◽  
pp. 49-55
Author(s):  
M. Ain Zubaidah ◽  
N.A. Asli ◽  
Mohamad Rusop ◽  
Saifollah Abdullah
Keyword(s):  
Porous Silicon ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Volume Ratio ◽  
Visible Range ◽  
Silicon Nanostructures ◽  
Etching Time ◽  
Light Emitting ◽  
Flat Screen ◽  
P Type

For this experiment, the main purpose of this experiment is to determine the electroluminescence of PSiNs samples with optimum electrolyte volume ratio of photo-electrochemical anodisation. PSiNs samples were prepared by photo-electrochemical anodisation by using p-type silicon substrate. For the formation of PSiNs on the silicon surface, a fixed current density (J=20 mA/cm2) and 30 minutes etching time were applied for the various electrolyte volume ratio. Volume ratio of hydrofluoric acid 48% (HF48%) and absolute ethanol (C2H5OH), HF48%:C2H5OH was used for sample A (3:1), sample B (2:1), sample C (1:1), sample D (1:2) and sample E (1:3). The light emission can be observed at visible range. The effective electroluminescence was observed for sample C. Porous silicon nanostructures light–emitting diode (PSiNs-LED) has high-potential device for future flat screen display and can be high in demand.

Relationships Between Photoluminescence Spectra and Porosity of Porous Silicon

1994 ◽  
Vol 332 ◽  
Author(s):  
H.Z. Song ◽  
L.Z. Zhang ◽  
B.R. Zhang ◽  
G.G. Qin
Keyword(s):  
Porous Silicon ◽  
Quantum Confinement ◽  
Light Emission ◽  
Photoluminescence Spectra ◽  
Lower Side ◽  
Si Substrates ◽  
Peak Energy ◽  
P Type ◽  
Confinement Model

ABSTRACTIt was found that porous silicon (PS) layers formed on 0.01 Ωcm (111) and 0.02 Ωcm (100) Si substrates show high photoluminescence (PL) peak energies on both lower and higher porosity sides and a minimum of PL peak energy at the moderate porosity, while those formed on 0.8 and 10Ωcm (111) p-type Si substrates show an increase of PL peak energy with porosity on the lower side and a saturation of PL peak energy with porosity on the higher side. These experimental facts are not consistent with the quantum confinement model for light emission of PS, which predicts a monotonous increase of PL peak energy with PS porosity.

Theory of Porous Silicon Injection Electroluminescence

1992 ◽  
Vol 283 ◽  
Author(s):  
H. Paul Maruska ◽  
F. Namavar ◽  
N. M. Kalkhoran
Keyword(s):  
Porous Silicon ◽  
Light Emission ◽  
Forward Bias ◽  
Interface States ◽  
Light Emitting ◽  
Long Term Stability ◽  
Quantum Confinement Effects ◽  
Current Path ◽  
Yellow Orange ◽  
P Type

ABSTRACTWe discuss the operation of porous silicon light-emitting diodes prepared as heterojunctions between n-type In2O3:Sn (ITO) and p-type silicon nanostructures, exhibiting quantum confinement effects. The transparent ITO affords light emission through the top surface of the device, as well as providing passivation and hence long term stability. We describe a model for the injection of minority carrier electrons into the porous silicon regions, which results in the emission of yellow-orange DC electroluminescence. A detailed study of the forward bias current-voltage characteristics of the devices will be given, which allows calculations of the densities of interface states. A tendency to pin the hole fermi energy near the neutral level, φ0, is shown to control the extraction of majority carriers. Methods for improving LED efficiency by alleviating a parasitic shunt current path through interface states will be addressed.

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