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.

scholarly journals Morphology and FT IR spectra of porous silicon

2017 ◽  
Vol 68 (7) ◽  
pp. 53-57 ◽  
Author(s):  
Martin Kopani ◽  
Milan Mikula ◽  
Daniel Kosnac ◽  
Jan Gregus ◽  
Emil Pincik
Keyword(s):  
Porous Silicon ◽  
Ir Spectra ◽  
Silicon Layer ◽  
Porous Silicon Layer ◽  
Layer Formation ◽  
Porous Si ◽  
Ft Ir ◽  
P Type ◽  
Type Sample ◽  
Ftir Investigation

AbstractThe morphology and chemical bods of p-type and n-type porous Si was compared. The surface of n-type sample is smooth, homogenous without any features. The surface of p-type sample reveals micrometer-sized islands. FTIR investigation reveals various distribution of SiOxHycomplexes in both p-and n-type samples. From the conditions leading to porous silicon layer formation (the presence of holes) we suggest both SiOxHyand SiFxHycomplexes in the layer.

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.

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.

New Concepts for the Development of Active Functional Polymers for p and n-Type OFET- Applications

2006 ◽  
Vol 965 ◽  
Author(s):  
Silvia Janietz ◽  
Udom Assawapirom ◽  
Dessislava Sainova
Keyword(s):  
Field Effect ◽  
Main Chain ◽  
Diffusion Processes ◽  
Colloidal Dispersions ◽  
Ambient Atmosphere ◽  
Polymer Main Chain ◽  
Acceptor Dopant ◽  
Chain Ladder ◽  
The Stability ◽  
P Type

ABSTRACTHere we present a concept to improve the field effect transistor performance of P3HT in terms of threshold voltage stability as well as the stability in ambient atmosphere by introducing a strong acceptor dopant in the main polymer chain. In our concept the direct introduction of the acceptor dopant in the polymer main chain ensures the strucural stability against diffusion processes. P3HTs with different contents of acceptor molecules which are fixed linked in the main chain of the polymer , have been synthesized using the McCullough Grignard metathesis method. As acceptor unit has been integrated tetrafluorbenzene (TFB). The introduced dopant amount has been varied in order to obtain an optimum between the processability of the polymers and the resultant transistor performance.Compared to the p-type semionducting polymers the n-type organic materials are markedly less developed. Recently an interesting solution to this task has been proposed in the form of a conjugated ladder-type poly (benzo-bisimidazobenzo-phenanthroline) (BBL) showing either ambipolar or n-type field effect properties dependent upon the sample preparation and processing. However this rigid-chain ladder polymer is not soluble in the common organic solvents resulting in a rather complicated technological transfer. We report the significant improvement of the BBL-processing utilizing aqueous colloidal dispersions and their OFET-application. The resultant devices demonstrate ambipolar electronic transport with charge carrier mobilities in the range of 10−5 cm2/Vs without specific optimization procedures..

Luminescence Activation of Porous Silicon by Post-Anodization Treatment

1992 ◽  
Vol 283 ◽  
Author(s):  
A. Kux ◽  
F. Muller ◽  
F. Koch
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Porous Silicon ◽  
Depth Distribution ◽  
Electrochemical Etching ◽  
Relative Importance ◽  
Porous Si ◽  
Ambient Conditions ◽  
Photochemical Etching ◽  
P Type

ABSTRACTWe prepare “nonluminescing” porous Si by electrochemical etching (50 mA/cm2 in 50% HF diluted 1:1 with ethanol) of 1 Ω(100) p-type wafers in the absence of light in order to study the subsequent luminescence activation by postprocessing. The treatments are: photochemical etching, ageing under ambient conditions, thermal oxidation. The study reveals remarkable inhomogeneities in the depth distribution of the luminescence and allows us to comment on the relative importance of particle size, spin density and chemical composition for the luminescence.

Lifetime Measurements of Stain Etched and Passivated Porous Silicon

2003 ◽  
Vol 762 ◽  
Author(s):  
Ricardo Guerrero-Lemus ◽  
Fathi A. Ben-Hander ◽  
Cristoffer Ballif ◽  
Ali Kenanoglu ◽  
Dietmar Borchert ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Vapour Deposition ◽  
Surface Passivation ◽  
Chemical Vapour ◽  
Lifetime Measurements ◽  
Porous Layers ◽  
Si Substrates ◽  
Before And After ◽  
P Type ◽  
Weak Influence

AbstractIn this work we present the first experimental study of photocarrier lifetimes in p-type and n-type Si substrates in which stain etched porous silicon (PS) has been formed on the surface. The lifetime values have been obtained before and after the surface passivation of the samples. The surface pasivation has been produced by two different techniques: (i) hydrogen passivation by immersion of the samples in a HF solution; and (ii) deposition of SiNx in a plasma enhanced chemical vapour deposition system. The results show a degradation of the photocarrier lifetime when the porous layers are not adequately passivated. This lifetime degradation is mainly associated to a large concentration of rapid recombination centres located at the Si/PS interface. We have also detected a weak influence of the PS outermost dangling bonds to the photocarrier lifetimes.

Metastability of Luminescent Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
S. Mtyazaki ◽  
K. Sakamoto ◽  
K. Shiba ◽  
M. Hirose
Keyword(s):  
Porous Silicon ◽  
Luminescence Intensity ◽  
Chemical Etching ◽  
Anomalous Temperature Dependence ◽  
Porous Si ◽  
Anomalous Temperature ◽  
Type C ◽  
P Type ◽  
Quenching Phenomenon ◽  
Subsequent Chemical

ABSTRACTPhotoluminescence from l–3μm thick porous Si layers prepared by anodization of p-type c-Si wafers and subsequent chemical etching exhibits an anomalous temperature dependence and light-induced degradation. The luminescence intensity is almost quenched at temperatures below 30K and recovered by laser irradiation at 48K. This quenching phenomenon is not observed for PS thicker than 10μm. The luminescence fatigue is partially recovered by annealing at 150°C for 5min during which no further oxidation takes place. These observations are interpreted in terms of the structural metastability of hydrogen-terminated porous Si.

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

scholarly journals Room-Temperature H2 Gas Sensing Characterization of Graphene-Doped Porous Silicon via a Facile Solution Dropping Method

2017 ◽  
Author(s):  
Nu Si A Eom ◽  
Hong-Baek Cho ◽  
Yoseb Song ◽  
Woojin Lee ◽  
Tohru Sekino ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Electrochemical Etching ◽  
Sensor Material ◽  
Sensing Mechanism ◽  
Si Substrates ◽  
H2 Sensor ◽  
P Type

In this study, a graphene-doped porous silicon (G-doped/p-Si) substrate for low ppm H2 gas detection by an inexpensive synthesis route was proposed as a potential noble graphene-based gas sensor material and to understand the sensing mechanism. The G-doped/p-Si gas sensor was synthesized by a simple capillary force-assisted solution dropping method on p-Si substrates, whose porosity was generated through an electrochemical etching process. G-doped/p-Si was fabricated with various graphene concentrations and exploited as a H2 sensor operated at room temperature. The sensing mechanism of the sensor with/without graphene decoration on p-Si was proposed to elucidate the synergetic gas sensing effect generated from the interface between the graphene and p-type silicon.

Tem Study of Porous Silicon Fabricated from N- and P-Type Doped Polycrystalline Films

1996 ◽  
Vol 452 ◽  
Author(s):  
L. Haji ◽  
Y. Le Thomas ◽  
F. Chane Che Lai ◽  
P. Joubert
Keyword(s):  
Porous Silicon ◽  
Pore Formation ◽  
Single Crystal Silicon ◽  
Extended Defects ◽  
Crystal Silicon ◽  
Cross Sectional ◽  
Si Substrates ◽  
Transmission Electron ◽  
Polycrystalline Silicon Films ◽  
P Type

AbstractThe formation of porous silicon (PS) from n/p, n+/p and p+/n structures carried from polycrystalline silicon films (poly-Si) deposited on single crystal silicon (c-Si) substrates was studied by cross-sectional transmission electron microscopy. Our results clearly show that the pore formation in such structures involve the extended defects of the poly-Si film. The role played by these defects depends on the doping type and level, and on whether the anodization is performed under illumination or not.

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