The Microstructure and Characteristics of Luminescent Porous Silicon Film Prepared by the Physicochemical

2010 ◽  
Vol 29-32 ◽  
pp. 566-570
Author(s):  
Xiao Jun Wan ◽  
Hui Xia Jin
Keyword(s):  
Porous Silicon ◽  
Chemical Treatment ◽  
Electrochemical Etching ◽  
Silicon Film ◽  
Ultrasonic Waves ◽  
Silicon Films ◽  
Chemical Effect ◽  
Etching Solution ◽  
Hydrogen Bubbles ◽  
Effective Technology

The special physicochemical environment caused by sonic-vacating provides an important outlet for the preparation of highly efficient luminescent porous silicon films. Experimental results show that sonic—chemical treatment is an effective technology for the improvement of the microstructure of porous silicon, and the luminescent efficiency and stability thereof. Luminescent porous silicon films, prepared by ultrasonic—enhanced anode electrochemical etching, display better qualities than the samples prepared by conventional methods widely used at present. This ultrasonic—chemical effect roots in sonic—vacating, i.e. the generation, formation and rapid collapse of bubbles in the etching solution. In the process of the porous silicon being etched, the escape rate and caving-in of hydrogen bubbles in the pores is increased as a result of the work of the ultrasonic waves, which is helpful to the vertical etching of the pores.

Effect of the composition of electrolyte on separation of porous silicon film by electrochemical etching

2003 ◽  
Vol 197 (2) ◽  
pp. 507-511 ◽  
Author(s):  
C. S. Solanki ◽  
R. R. Bilyalov ◽  
J. Poortmans ◽  
J.-P. Celis ◽  
J. Nijs
Keyword(s):  
Porous Silicon ◽  
Electrochemical Etching ◽  
Silicon Film ◽  
Effect Of The Composition

Optical Properties of Free-Standing Ultrahigh Porosity Silicon Films Prepared by Supercritical Drying

1996 ◽  
Vol 452 ◽  
Author(s):  
J. Von Behren ◽  
P. M. Fauchet ◽  
E. H. Chimowitz ◽  
C. T. Lira
Keyword(s):  
Porous Silicon ◽  
Electrochemical Etching ◽  
Supercritical Drying ◽  
Silicon Films ◽  
Index Of Refraction ◽  
Free Standing ◽  
Crystal Silicon ◽  
Si Substrates ◽  
Type C ◽  
P Type

AbstractHighly luminescent free-standing porous silicon thin films of excellent optical quality have been manufactured by using electrochemical etching and lift-off steps combined with supercritical drying. One to 50 μm thick free-standing layers made from highly (p+) and moderately (p) Boron doped single crystal silicon (c-Si) substrates have been produced with porosities (P) up to 95 %. The Fabry-Pérot fringes observed in the transmission and photoluminescence (PL) spectra are used to determine the refractive index. At the highest P the index of refraction is below 1.2 from the IR to 2 eV. The absorption coefficients follow a nearly exponential behavior in the energy range from 1.2 eV and 4 eV. The porosity corrected absorption spectra of free-standing films made from p type c-Si substrates are blue shifted with respect to those prepared from p+ substrates. For P > 70 % a blue shift is also observed in PL. At equal porosities the luminescence intensities of porous silicon films made from p+ and p type c-Si are different by one order of magnitude.

Self-Similarity of Electrochemically-Deposited Copper Films on Porous Silicon

2010 ◽  
Vol 428-429 ◽  
pp. 515-518
Author(s):  
Lan Li Chen ◽  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Porous Silicon ◽  
Silicon Film ◽  
Silicon Films ◽  
The Self ◽  
Copper Films ◽  
Self Similarity ◽  
Control Electrode ◽  
Smooth Control ◽  
Electrochemically Deposited ◽  
Scanning Electron

The microstructures of electrochemically-deposited copper control electrode on semiconducting porous silicon films were investigated with scanning electron microscopy. Our results showed that smooth control electrode could be grown in areas far from the edge of porous silicon film while irregular electrode was formed on the circular edge of porous silicon films. The self-similarity of the electrochemically-deposited copper control electrode was analyzed in details.

Photoluminescence of Liquid Crystal Infiltrated Porous Silicon Film

2010 ◽  
Vol 663-665 ◽  
pp. 812-815 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Liquid Crystal ◽  
Porous Silicon ◽  
Nematic Liquid Crystal ◽  
Silicon Film ◽  
Luminescent Properties ◽  
Silicon Films ◽  
The Other ◽  
Deep Blue ◽  
Pl Spectrum ◽  
The Cost

We have investigated the photoluminescence (PL) of a porous silicon film in which a typical nematic liquid crystal 4-pentyl-4’-cyanobiphenyl infiltrated. Before the liquid crystal filtration, the PL spectrum of the porous silicon film is comprised of two luminescent bands, one of which is located at about 600 nm whereas the other of which is located at about 450 nm. After the liquid crystal filtration, the porous silicon film gives off intense deep-blue PL with its peak located at about 400 nm at the cost of the complete quenching of the PL from the original porous silicon film. Our results have demonstrated that the luminescent properties of porous silicon films can be dramatically modified by liquid crystal infiltration.

POROUS SILICON: INFLUENCE OF ETCHING TEMPERATURE ON MICROSTRUCTURE AND LUMINESCENCE

2001 ◽  
Vol 08 (05) ◽  
pp. 429-433 ◽  
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.

Preparation, Properties and Applications of Free-Standing Porous Silicon Films

1994 ◽  
Vol 358 ◽  
Author(s):  
J. Von Behren ◽  
L. Tsybeskov ◽  
P. M. Fauchet
Keyword(s):  
Porous Silicon ◽  
Near Infrared ◽  
Electrochemical Etching ◽  
Supercritical Drying ◽  
Silicon Films ◽  
Index Of Refraction ◽  
High Porosity ◽  
Large Area ◽  
Free Standing ◽  
Lift Off

ABSTRACTUsing special electrochemical etching and lift-off steps, we have fabricated large-area freestanding porous silicon films in the thickness range from 0.1 μm to 50 μm. Their transmission is near 100% in the near infrared which is indicative of very high porosity/low index of refraction films. These optically flat and homogeneous films exhibit no surface and bulk scattering, despite the fact that they did not undergo supercritical drying. The relationship between the absorption coefficient, the luminescence spectrum, and the chemical and structural properties is examined as a function of preparation and post-treatment conditions. Because of their superior optical properties, these films are suitable for many device applications.

Optically Encoded Smart Dust from DBR Porous Silicon

2006 ◽  
Vol 321-323 ◽  
pp. 53-56 ◽  
Author(s):  
Bong Ju Lee ◽  
Sung Gi Kim ◽  
Hong Lae Sohn
Keyword(s):  
Porous Silicon ◽  
Chemical Sensor ◽  
Electrochemical Etching ◽  
Silicon Film ◽  
Bragg Reflector ◽  
Organic Solution ◽  
Scanning Electron Micrograph ◽  
Distributed Bragg Reflector ◽  
Organic Vapors ◽  
Smart Dust

Distributed Bragg reflector (DBR) porous silicons exhibiting unique reflectivity were successfully obtained by an electrochemical etching of silicon wafer using square wave currents. Optically encoded smart dust which retained optical reflectivity was obtained from DBR porous silicon film in organic solution by using ultra-sono method. The size of optically encoded smart dust was measured by field emission scanning electron micrograph (FESEM) and was about 500 nm to few microns depending on the duration of sonication. Investigation for the optical characteristics of smart dust revealed that smart dust could be useful for application such as chemical sensor for detecting organic vapors.

On the morphology of stain-etched porous silicon films

1998 ◽  
Vol 80 (1-4) ◽  
pp. 163-167 ◽  
Author(s):  
L. Schirone ◽  
G. Sotgiu ◽  
M. Montecchi
Keyword(s):  
Porous Silicon ◽  
Silicon Films
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