Effects of local ambient atmosphere on the stability of electroluminescent porous silicon diodes

1995 ◽  
Vol 77 (11) ◽  
pp. 5936-5941 ◽  
Author(s):  
Libing Zhang ◽  
Jeffery L. Coffer ◽  
Bruce E. Gnade ◽  
DaXue Xu ◽  
Russell F. Pinizzotto
Keyword(s):  
Porous Silicon ◽  
Ambient Atmosphere ◽  
The Stability

The Influence of Local Ambient Atmosphere on the Electroluminescent Stability of Porous Silicon Diodes

1994 ◽  
Vol 358 ◽  
Author(s):  
Libing Zhang ◽  
Jeffery L. Coffer ◽  
Bruce E. Gnade ◽  
DaXue Xu ◽  
Russell F. Pinizzotto
Keyword(s):  
Porous Silicon ◽  
Surface Oxidation ◽  
Spectroscopic Studies ◽  
Inert Gases ◽  
Ambient Atmosphere ◽  
Porous Si ◽  
Si Substrates ◽  
Integrated Intensity ◽  
The Stability ◽  
P Type

ABSTRACTIn this work, the influence of surrounding ambient atmosphere on the stability of electroluminescent (EL) porous Si (PS) diodes fabricated from anodic oxidation of epitaxially grown p-type layers on n-type Si substrates is investigated. These structures are characterized using photoluminescence (PL), electroluminescence (EL), and infrared (IR) spectrosopies, as well as scanning electron microscopy (SEM). Such structures yield orange emission with maxima near 620 nm upon the application of moderate applied voltages (3-7 V). In strong oxidizing environments, EL intensity degrades completely within 30 minutes; in contrast, the integrated intensity remains essentially unchanged in the same timeframe in the presence of a vigorous flow of inert gases such as nitrogen and argon. Infrared spectroscopic studies strongly suggest that electroluminescence degradation is related to porous silicon surface oxidation.

The Photoluminescence Enhancement and Stability of Porous Silicon by Cathodic Reduction and Acid Treatment

2014 ◽  
Vol 887-888 ◽  
pp. 458-461
Author(s):  
Chang Qing Li ◽  
Kun Wang ◽  
Pei Jia Liu ◽  
Qi Ming
Keyword(s):  
Electron Microscope ◽  
Porous Silicon ◽  
Acid Treatment ◽  
Cathodic Reduction ◽  
Luminescence Properties ◽  
Sem Images ◽  
Photoluminescence Enhancement ◽  
The Stability ◽  
Scanning Electron ◽  
Cathode Reduction

Porous silicon (PSi) was fabricated by using electrochemical anodic etching method. Then acid treatment and cathode reduction treatment were employed to improve the luminescence properties and stability of PSi material. Photoluminescence (PL) measurements and scanning electron microscope (SEM) were used to observe the luminescence properties and microstructure of samples, respectively. The results of PL measurements showed that the PL intensity and the stability of luminescence of samples after cathodic reduction and acid treatment were significantly improved. The SEM images showed that the porosity of PSi may be increased through the cathodic reduction treated.

Light Controlled Photoluminescence Relaxation in Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
R. Czaputa ◽  
R. Fritzl ◽  
A. Popitsch
Keyword(s):  
Porous Silicon ◽  
Chemical Structure ◽  
Room Temperature ◽  
Relaxation Effect ◽  
Ambient Atmosphere ◽  
Surface Chemical ◽  
Dangling Bond ◽  
Nanoporous Silicon ◽  
Pl Intensity ◽  
Modification Of The Surface

ABSTRACTWe report results of photoluminescence (PL), FTIR and ESR investigations on nanoporous silicon (PS) where a reversible PL intensity relaxation effect in the chemically oxidised material is observed. To be activated the effect needs, however, additional preparation steps including light irradiation and ageing in ambient atmosphere. After illumination with visible light, the PL intensity is remarkably diminished. However it recovers in the dark within the time scale of minutes to hours under ambient atmosphere at room temperature. This cycle can be repeated several times. We show that the variation of the PL intensity is anticorrelated to an ESR signal attributed to silicon dangling bonds. From the IR spectrum, however, no significant change of the pore surface chemical structure can be observed during a cycle. Therefore we conclude that the variation of the PL intensity is rather controlled by a metastable change in the number of dangling bond centers than by modification of the surface chemistry in the porous silicon system.

Effect of Ambient Atmosphere on Thin Film Reaction of Si3N4 with Ti

1989 ◽  
Vol 170 ◽  
Author(s):  
Seshu B. Desu ◽  
J. Ashley Taylor
Keyword(s):  
Layer Structure ◽  
Chemical Vapor ◽  
Product Formation ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Pressure Chemical ◽  
Rapid Thermal Annealer ◽  
The Stability ◽  
Increasing Temperature

AbstractThe reaction of sputtered deposited Ti films of 100 nm thick with low pressure chemical vapor deposited Si3N4 films (300 nm thick) was studied in N2 or Ar, in a rapid thermal annealer. Reactions are followed using x-ray diffraction, Auger electron spectroscopy, and transmission electron microscopy. In argon, the Si3N4 and Ti reaction at low temperatures led to the product formation of two layer structure (TiN/Ti5Si3), with some contaminant oxygen and nitrogen released from the reaction uniformly dissolved throughout the remaining unreacted Ti. At higher temperatures, a three layer structure, TiN/TixSiy/TiN, on unreacted Si3N4 was developed. With increasing temperature the value of x and y decreased from 5 to 0 and 3 to 1, respectively. Reactions in N2 ambient, irrespective of temperature, always produced the three layer structure, but the thickness of TixSiy layer was much smaller than that produced in argon ambient for the corresponding temperatures. The reaction mechanism can be explained in terms of relative diffusion coefficients and the stability of the interfaces.

Role of nanocrystalline ZnO coating on the stability of porous silicon formed on textured (100) Si

2013 ◽  
Vol 285 ◽  
pp. 564-571 ◽  
Author(s):  
Daisy Verma ◽  
Shailesh N. Sharma ◽  
Aneeta Kharkwal ◽  
G. Bhagavannarayana ◽  
Mahesh Kumar ◽  
...  
Keyword(s):  
Porous Silicon ◽  
The Stability

Effects of Amorphous Carbon Films on the Performance of Porous Silicon Electroluminescence

2002 ◽  
Vol 737 ◽  
Author(s):  
Bernard Gelloz ◽  
Nobuyoshi Koshida
Keyword(s):  
Porous Silicon ◽  
Amorphous Carbon ◽  
Chemical Stability ◽  
Indium Tin Oxide ◽  
Carbon Film ◽  
Carbon Films ◽  
Positive Effects ◽  
Thin Carbon ◽  
Thin Carbon Film ◽  
The Stability

ABSTRACTEfficient electroluminescence (EL) is obtained at low operating voltages (<3 V) from n+-type silicon- electrochemically oxidized thin nanocrystalline porous silicon (PS)-amorphous carbon-Indium tin oxide (ITO) junctions. The effects of a few nanometer thick amorphous carbon film between PS and ITO on the EL characteristics have been investigated. The carbon film enhances the stability. The EL efficiency is improved due to a reduction of current density and an increase in EL intensity. In addition, the reproducibility from device to device is very much improved by the carbon film. The enhancement in stability should originate from the capping of PS by the carbon film and the high chemical stability of carbon and Si-C bonds, which should prevent PS oxidation. The carbon film acts as an efficient buffer layer between PS and ITO, resulting in enhanced mechanical, electrical and chemical stability of the top contact and providing high reproducibility. The thin carbon film has only positive effects on all the EL characteristics. This is a very important step towards application.

Phase equilibria among the superconductors in the Y2O3–BaO–Cu–O system

1999 ◽  
Vol 14 (9) ◽  
pp. 3511-3517 ◽  
Author(s):  
Zhigang Zhou ◽  
Alexandra Navrotsky
Keyword(s):  
Enthalpy Of Formation ◽  
Bulk Composition ◽  
Standard Enthalpy Of Formation ◽  
Reaction Calorimetry ◽  
Ambient Atmosphere ◽  
Free Energies ◽  
High Temperature Reaction ◽  
The Stability ◽  
Narrow Area ◽  
Phase Relationships

The enthalpy of formation of Y2Ba4Cu7O14.864 at room temperature has been determined by using high-temperature reaction calorimetry. The standard enthalpy of formation of the 247 phase is ΔH°f = −5463 ± 18 kJ mol−1. Phase relationships among the superconductors, namely, the 123, 124, and 247, are assessed. It is intrinsic that impurity phases, such as Y2Cu2O5, BaCuO2, CuO, etc., coexist with the superconductors at equilibrium. Equilibria among the superconductor phases in the Y2O3–BaO–Cu–O system have been determined. The results show that, at the 124 bulk composition, the 247 phase coexists with the excess CuO in a narrow area of pO2 ∼ T space confined by the stability fields of the 124 phase and a mixture of the 123 + CuO. The standard free energies of carbonation and hydration of the 247 phase are also determined, which are −629 ± 13 kJ mol−1 and −873 ± 45 kJ mol−1, respectively. Like the 123 and 124 phases, the 247 phase is thermodynamically unstable for corrosion by water vapor and carbon dioxide in ambient atmosphere.

Comparative Analysis of the Effect of Immersion of Porous Silicon in Aqueous Solutions of Li and Fe Salts on the Stability, Peak Position and Intensity of its Photoluminescence

2018 ◽  
Vol 386 ◽  
pp. 75-79
Author(s):  
Nikolay G. Galkin ◽  
Dmitrii Tkhyarbonovich Yan ◽  
Konstantin N. Galkin ◽  
Evgeniy Anatolievich Chusovitin ◽  
Mikhail Victorovich Bozhenko
Keyword(s):  
Porous Silicon ◽  
Aqueous Solutions ◽  
Blue Shift ◽  
Peak Position ◽  
Maximum Increase ◽  
Long Term Storage ◽  
Low Concentrations ◽  
The Stability ◽  
Term Storage

In the process of comparative studies of immersing layers of porous silicon (PS) in aqueous solutions of LiBr and Fe (NO3)3 with subsequent long-term storage up to 150 days, it is established that there exists: (1) the range of concentrations of LiBr (S/2 - S/4) and Fe (NO3)3 (0.2 M), which provide the maximum increase in the intensity of PL; (2) at low concentrations of both salts, a blue shift of the PL peaks and an increase in their intensity are observed during the long-term storage, which is associated with a decrease in the size of the NC in the PS and the influence of silicon bonds with lithium or iron ions; (3) full protection of the PS layer is observed in case of immersion in Fe (NO3)3 with a concentration of 0.7M - 0.8M.

Perspectives of Porous Silicon Multilayer Technology

1998 ◽  
Vol 536 ◽  
Author(s):  
M. Thönissen
Keyword(s):  
Porous Silicon ◽  
Multilayer Systems ◽  
Interference Filters ◽  
Electrical Control ◽  
The Stability ◽  
And Diffusion ◽  
Multiple Interference ◽  
Multilayer Technology

AbstractThe exact control and adjustment of the etch parameters is important for the fabrication of well defined and reproducible devices based on porous silicon (PS) multilayers. In this paper the etch parameters “electrolyte volume” and “diffusion in the electrolyte” will be discussed as specific problems during a commercial fabrication of multilayer applications. Additionally the stability of the filter characteristics of multilayer systems will be analyzed by changing the climatic environments. New perspectives of multilayer applications will be given, e. g. the electrical control of filters, spatially graded interference filters and multiple interference filters on one sample.

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