Manufacture of Submicron Light-Emitting Porous Silicon Areas for Miniature LEDs

1995 ◽  
Vol 380 ◽  
Author(s):  
S. P. Duttagupta ◽  
C. Peng ◽  
L. Tsybeskov ◽  
P. M. Fauchet
Keyword(s):  
Electron Beam ◽  
Porous Silicon ◽  
Crystalline Silicon ◽  
Group Formation ◽  
Nanometer Scale ◽  
Ion Milling ◽  
Light Emitting ◽  
Atomic Force ◽  
Mapping Techniques ◽  
Trilayer Process

ABSTRACTWe have investigated several methods to form submicron-size porous silicon regions. Porous silicon can emit light from the violet to past 1.5 μm with high photoluminescence efficiency at room temperature. It is composed of a high density of nanometer-scale crystalline silicon wires or dots. To integrate light-emitting porous silicon (LEPSi) LEDs with conventional Si microelectronics, it is necessary to produce miniature LEPSi regions adjacent to fully protected crystalline silicon regions. These techniques can be divided into two groups. In the first group formation of LEPSi is prevented during electrochemistry. Using optical and electron beam lithography, and a trilayer process with silicon nitride or amorphization by ion-implantation, we have made LEPSi patterns as small as 100 nm. In the second group, the formation of LEPSi during electrochemistry is enhanced by ion-milling or reactive ion-etching which we have found to help the pore nucleation. We have used a variety of mapping techniques, such as photoluminescence, atomic force and electron beam microscopies, to characterize the sharpness of the interface between the porous silicon and crystalline silicon regions.

scholarly journals Influence of applied current density on the nanostructural and light emitting properties of n-type porous silicon

2015 ◽  
Vol 29 (15) ◽  
pp. 1550093 ◽  
Author(s):  
A. Cetinel ◽  
N. Artunç ◽  
G. Sahin ◽  
E. Tarhan
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Pore Diameter ◽  
Crystalline Silicon ◽  
Peak Shift ◽  
Raman Peak ◽  
Light Emitting ◽  
Nanocrystallite Size ◽  
Raman Peak Shift ◽  
Pore Depth

Effects of current density on nanostructure and light emitting properties of porous silicon (PS) samples were investigated by field emission scanning electron microscope (FE-SEM), gravimetric method, Raman and photoluminescence (PL) spectroscopy. FE-SEM images have shown that below 60 mA/cm 2, macropore and mesopore arrays, exhibiting rough morphology, are formed together, whose pore diameter, pore depth and porosity are about 265–760 nm, 58–63 μ m and 44–61%, respectively. However, PS samples prepared above 60 mA/cm 2 display smooth and straight macropore arrays, with pore diameter ranging from 900–1250 nm, porosity of 61–80% and pore depth between 63–69 μ m . Raman analyses have shown that when the current density is increased from 10 mA/cm 2 to 100 mA/cm 2, Raman peaks of PS samples shift to lower wavenumbers by comparison to crystalline silicon (c-Si). The highest Raman peak shift is found to be 3.2 cm -1 for PS sample, prepared at 90 mA/cm 2, which has the smallest nanocrystallite size, about 5.2 nm. This sample also shows a pronounced PL, with the highest blue shifting, of about 12 nm. Nanocrystalline silicon, with the smallest nanocrystallite size, confirmed by our Raman analyses using microcrystal model (MCM), should be responsible for both the highest Raman peak shift and PL blue shift due to quantum confinement effect (QCE).

High Spatial Resolution Mapping of Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
E. Ettedgui ◽  
C. Peng ◽  
L. Tsybeskov ◽  
Y. Gao ◽  
P. M. Fauchet ◽  
...  
Keyword(s):  
Porous Silicon ◽  
High Spatial Resolution ◽  
Growth Conditions ◽  
Cross Sectional ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force ◽  
Resolution Mapping ◽  
Mapping Techniques ◽  
Sectional Analysis

ABSTRACTPorous silicon (PSI) samples with high photoluminescence (PL) efficiency were examined using microscopic mapping techniques including scanning election microscopy (SEM) and spatially resolved photoluminescence (SRPL). Studies of the growth conditions indicate that the homogeneity of the PL and the surface roughness of the sample depend on the preparation procedure of the PSI layer. SEM and spatially-resolved reflectance scans of an n-type sample with a PSI layer on the order of 100 μm reveal a highly fractured surface. SRPL of the same sample shows non uniform PL on a scale of 5 μm. Cross-sectional analysis of the samples with SRPL and SEM reveals the intricate multilayer structure of the PSI film. The top portion of the PSI film is largely responsible for the PL and is composed of isolated column-like structures. We have also observed cross-shaped structures reminiscent of stress fractures on the surface of PSI films using SEM or optical microscopy. Furthermore, atomic force microscopy (AFM) and SEM measurements of the surface of PSI films of intermediate thickness reveal that samples which appear smooth on ̃ lμm scale are actually covered with clumped structures on the order of 100 to 150 nm.

Crystalline silicon quantum dots formation by tailored plasma irradiation: self-structurization, nucleation and growth accelerations, and size control

Nanoscale ◽  
2021 ◽  
Author(s):  
Daehan Choi ◽  
Jung Hyung Kim ◽  
Deuk Chul Kwon ◽  
Chae Ho Shin ◽  
Hyun Rhu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Silicon Nanoparticles ◽  
Crystalline Silicon ◽  
Light Emitting Diode ◽  
Size Control ◽  
Nucleation And Growth ◽  
Nanometer Scale ◽  
Light Emitting ◽  
Plasma Irradiation ◽  
Growth Accelerations

Crystalline silicon nanoparticles under nanometer scale have been garnering great interest in many different optoelectronic applications such as photovoltaic and light-emitting-diode devices. Formation, crystallization, and size control of silicon nanoparticles...

The Self-assembled Deposition on the Surface of Mono-crystalline Silicon Induced by High-Current Pulsed Electron Beam

2017 ◽  
Vol 36 (6) ◽  
pp. 593-597
Author(s):  
Zhang Conglin ◽  
Guan Qingfeng ◽  
Chen Jie ◽  
Yan Pengcheng ◽  
Lv Peng
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Crystalline Silicon ◽  
High Current ◽  
Pulsed Electron Beam ◽  
Atomic Force ◽  
Transmission Electron ◽  
Si Nanoparticles ◽  
Surface Microstructures ◽  
Pulsed Irradiation

AbstractHigh-current pulsed electron beam (HCPEB) technique was applied to irradiate the surface of mono-crystalline silicon wafers. Surface microstructures of the irradiated surface were investigated in detail by atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The experimental results show that HCPEB irradiation with energy density 4 J/cm2 caused evaporation of the irradiated surface. Subsequently, the evaporation Si-droplets was deposited to form Si-nanoparticles on the surface. Meanwhile, the structures of intensive plastic deformation were also introduced within the irradiated surface layer. The dislocation configurations with rectangular and approximate hexagonal network were formed on the surface of Si wafer after 5-pulsed irradiation. The periodic self-deposited structures appear to be related to the configuration of regular dislocations arrays, which were favorable locations for the deposited Si-nanoparticles.

Plasmons on Luminescent Porous Silicon Prepared with Ethanol and Critical Point Drying

1998 ◽  
Vol 536 ◽  
Author(s):  
O. Resto ◽  
L. F. Fonseca ◽  
S. Z. Weisz ◽  
A. Many ◽  
Y. Goldstein
Keyword(s):  
Electron Beam ◽  
Porous Silicon ◽  
Critical Point ◽  
Crystalline Silicon ◽  
Electrochemical Etching ◽  
Silicon Compound ◽  
Drying Process ◽  
Plasmon Energy ◽  
Etching Technique ◽  
Critical Point Drying

AbstractWe investigated the plasmon characteristics on luminescent porous silicon using electron energy loss spectroscopy. The samples were prepared from p-type crystalline silicon, (100) face, using the conventional electrochemical etching technique with the usual solution of HF, ethanol and water, followed by a critical point drying process. The energy of the bulk plasmon was measured both before and after sputter cleaning the sample with argon-ion bombardment. We found that initially the plasmon energy was slightly higher, ∼18 eV, than the plasmon energy of crystalline silicon. After sputter cleaning the sample with 5 keV Ar+ ions, the plasmon energy increased to ∼20 eV. Exposure to the electron beam used for the measurements caused a slow upward shift of the plasmon energy as a function of time, toward a saturation energy of 22-23 eV, an energy close to the plasmon energy of SiC. Auger spectroscopy performed in parallel showed an increasing carbon coverage. We prepared also samples without ethanol in the etching solution and/or with no critical point drying. Samples that did not undergo the critical point drying process showed consistently a practically constant plasmon energy, with almost no change upon sputtering and/or exposure to the electron beam. On the other hand, samples that were prepared with or without ethanol but using the critical point drying process, showed an appreciable increase in the plasmon energy upon exposure to the electron beam.We conclude that traces of CO2, used in the critical point drying process, are stored in the pores of the porous silicon surface and serve as a source of carbon. Apparently, upon activation by argon bombardment or by the electron beam, the carbon interacts with the porous Si surface forming a carbon-silicon compound, most probably SiC.

Analysis of the Structure of Light-emitting Porous Silicon by Raman Scattering

1991 ◽  
Vol 256 ◽  
Author(s):  
Zhifeng Sui ◽  
Patrick P. Leong ◽  
Irving P. Herman ◽  
Gregg S. Higashi ◽  
Henryk Temkin
Keyword(s):  
Porous Silicon ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Silicon Film ◽  
Characteristic Dimension ◽  
Raman Shift ◽  
Phonon Confinement ◽  
Island Size ◽  
Light Emitting ◽  
Silicon Islands

AbastracRaman spectra from a thick porous silicon film (∼100 μm) that strongly emits in the visible (∼ 6350 Å) at room temperature are obtained. An asymmetric peak with a Raman shift of ∼ 508 - 510 cm−1 and a width of ∼ 40 cm−1 is seen in every spectrum. This Raman feature resembles that of μc-Si, suggesting that the local structure of the porous silicon is a network of interconnected crystalline silicon islands with the island size in the nanometer range., and that the, shape of the islands is more sphere-like than rod-like. The characteristic dimension of the islands in these porous silicon films is estimated to be ∼ 2.5 - 3.0 nm on the basis of an empirical model calculation of phonon confinement.

Comparative Study of Light-Emitting Porous Silicon Anodized with Light Assistance and in the Dark

1993 ◽  
Vol 298 ◽  
Author(s):  
L. Tsybeskov ◽  
C. Peng ◽  
S.P. Duttagupta ◽  
E. Ettedgui ◽  
Y. Gao ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Comparative Study ◽  
Light Emission ◽  
Crystalline Silicon ◽  
Electrochemical Anodization ◽  
Light Emitting ◽  
Spatially Resolved ◽  
Different Types

AbstractIn this study, we compare two different types of light emitting porous silicon (LEpSi) samples: LEpSi anodized in the dark (DA) and LEpSi anodized with light assistance (LA). On the basis of photoluminescence (PL), Raman, FTIR, SEM, spatially resolved reflectance (SRR) and spatially resolved photoluminescence (SRPL) studies, we demonstrate that the luminescence in LA porous silicon is strong, easily tunable, very stable and originates from macropore areas. These attractive properties result from passivation by oxygen in the Si-O-Si bridging configuration that takes place during electrochemical anodization. In addition, we have been able to correlate light emission with the presence of crystalline silicon nanograins.

Photoluminescence from nano porous silicon prepared by photoelectrochemical etching of n-type single crystalline silicon

2000 ◽  
Vol 638 ◽  
Author(s):  
Chi-Woo Lee ◽  
Buem-Suck Kim ◽  
Dong-Il Kim ◽  
Nam-Ki Min ◽  
Suk-In Hong
Keyword(s):  
Porous Silicon ◽  
Electrolyte Concentration ◽  
Crystalline Silicon ◽  
Single Crystalline Silicon ◽  
Photoluminescence Spectra ◽  
Applied Potential ◽  
Photoelectrochemical Etching ◽  
Light Emitting ◽  
Silicon Materials ◽  
Illumination Wavelength

AbstractThe influence of operating parameters in producing light-emitting porous silicon materials was investigated in ethanolic solutions of hydrofluoric acid. Photoluminescence spectra depended on applied potential, the intensity and wavelength of illumination, and electrolyte concentration. When the applied potential and the illumination wavelength increased, the photoluminescence shifted to longer wavelength. Change in HF concentration resulted in different intensity in photoluminescence.

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