The Visible and the Infrared Luminescence Bands as a Tool for Characterization of the Porous Silicon Bandstructure

1994 ◽  
Vol 358 ◽  
Author(s):  
V. Petrova-Koch ◽  
T. Muschik ◽  
G. Polisski ◽  
D. Kovalev
Keyword(s):  
Porous Silicon ◽  
Low Temperature ◽  
Valence Band ◽  
Conduction Band ◽  
Porous Si ◽  
Surface Degradation ◽  
Infrared Luminescence

ABSTRACTThe visible and the infrared photoluminescence bands in porous Si have been studied at low temperature for two series of samples: one in which the size of the crystallites has been varied and another in which the degree of surface degradation has been changed. It is shown that the relation of the two bands can be explored for characterization of the porous Si bandstructure. The size- and the surface dependence of the valence band and of the conduction band related states is discussed. A model is proposed for explanation.

Photoluminescence of ZnO:Eu3+ Nanoflowers

2008 ◽  
Vol 8 (3) ◽  
pp. 1307-1311 ◽  
Author(s):  
Peter A. Tanner ◽  
Lixin Yu
Keyword(s):  
Low Temperature ◽  
Conduction Band ◽  
Selective Excitation ◽  
Ftir Spectra ◽  
Photoluminescence Spectra ◽  
Defect States ◽  
Hydrothermal Route ◽  
Broadband Emission ◽  
The Eu

The synthesis of ZnO:Eu3+ nanoflowers by a low-temperature hydrothermal route is described. Characterization of the materials was performed by ESEM, XRD and FTIR spectra. The 355 nm excited photoluminescence spectra at 10 K do not indicate the presence of Eu2+ or the ZnO defect states which give rise to green or red broadband emission. Excitation into the ZnO conduction band at low temperature does not give emission from Eu3+. Selective excitation of the Eu3+ emission shows that Eu3+ ions occupy a variety of different sites, of which one of them is similar to Eu3+ in C-type Eu2O3.

Structural Characterization of Porous Silicon Fabricated by Electrochemical and Chemical Dissolution of Si Wafers

1991 ◽  
Vol 256 ◽  
Author(s):  
S. Miyazaki ◽  
T. Yasaka ◽  
K. Okamoto ◽  
K. Shiba ◽  
K. Sakamoto ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Electron Beam Irradiation ◽  
Complete Recovery ◽  
Porous Si ◽  
Beam Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Disordered Structure ◽  
Visible Luminescence

ABSTRACTThe structure of porous silicon exhibiting efficient visible photoluminescence has been characterized by using Fourier transformed infrared absorption, Raman scattering and x-ray diffraction. It is shown that the lattice spacing in the porous Si layer expands by about 0.3% in the direction perpendicular to the surface and also a partially disordered structure is existing. Electron beam irradiation causes desorption of hydrogen and fluorine bonds which terminate the surface, resulting in the quenching of the visible luminescence. The chemical etching of such layer has led to complete recovery of the luminescence intensity as well as the hydrogen and fluorine bonds termination.

Oxidized porous silicon as a non-interfering support for luminescent dyes

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
G. Santamaría-Juárez ◽  
E. Gómez-Barojas ◽  
E. Quiroga-González ◽  
E. Sánchez-Mora ◽  
J. A. Luna-López
Keyword(s):  
Experimental Study ◽  
Porous Silicon ◽  
Low Temperature ◽  
Thermal Oxidation ◽  
Surface States ◽  
Large Contribution ◽  
Porous Si ◽  
Host Matrix ◽  
Oxidized Porous Silicon ◽  
Pl Spectrum

AbstractThe objective of this work is to elucidate the possibility to passivate the surface states of porous Si (PSi) by thermal oxidation to be used as a passive host matrix. It is known that a large contribution to the Photoluminescence (PL) of PSi comes from defects at the surface. This PL could overlap the PL of guest materials making it difficult to identify the details of the PL spectrum of the guest. We report on an experimental study about the effect of thermal oxidation at low temperature on the PL of PSi and on the functionalization of oxidized PSi with fluorescein. The background PL is minimized allowing a better detection of fluorescein molecules adsorbed on oxidized PSi.

Strain-Controlled High Mobility in Modulation Doped Si0.5Ge0.5/Ge/Si1-xGex Hetero-Structures

1989 ◽  
Vol 160 ◽  
Author(s):  
Masanobu Miyao ◽  
Eiichi Murakami ◽  
Hiroyuki Etoh ◽  
Kiyokazu Nakagawa
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Valence Band ◽  
Strain Field ◽  
High Mobility ◽  
Buffer Layers ◽  
Two Dimensional ◽  
Mbe Growth ◽  
Hetero Structure

AbstractFormation and characterization of a new hetero -structure of modulation doped p-Si0.5Ge0.5/Ge/Si1-xGex are comprehensively studied. In the MBE growth, thick Si1-xGex buffer layers are grown incommensurately at high temperature (520°C), and thin Si0.5Ge0.5/Ge layers are grown commensurately at low temperature (≦450°C). The strain field in the Ge channel layers can be precisely controlled by changing the Si composition (1-X) in the Si 1 -xGex buffer layers. As a result, a large energy discontinuity in the valence band (0.17 eV) is realized at the hetero -interface of p-Si0.5Ge0.5/Ge. This enables a high mobility of two -dimensional hole gas (4500 cm2/Vs) at 77 K.

Characterization of Erbium Doped SiO2 Layers Formed On Silicon By Spark Processing

1997 ◽  
Vol 486 ◽  
Author(s):  
John V. St. John ◽  
Jeffery L. Coffer ◽  
Young Gyu Rho ◽  
Patrick Diehl ◽  
Russell F. Pinizzotto ◽  
...  
Keyword(s):  
Rare Earth ◽  
Porous Silicon ◽  
Porous Si ◽  
Rare Earth Ion ◽  
Temperature Oxidation ◽  
X Ray ◽  
Near Ir ◽  
Erbium Doped ◽  
Er Doped

AbstractDeposition of a rare earth salt layer on a silicon substrate with subsequent spark processing yields a porous Si layer and SiO 2 cap doped with the rare earth ion. We have characterized luminescent Er-doped porous SiO2 on Si by scanning electron microscopy, energy dispersive Xray spectroscopy, as well as visible and near IR photoluminescence (PL) spectroscopies. Energydispersive x-ray maps indicate that the erbium concentration in the porous layer can be controlled by varying the molarity of the erbium solution deposited on the substrate prior to spark processing. Visible PL measurements reveal that the concentration of Er3+ is proportional to the resultant intensity of the visible fluorescence transitions; however, for the near IR fluorescence peak at 1.54 gim, self-quenching due to erbium clustering occurs at higher concentrations. Erbium-doped porous silicon layers can also be obtained by diffusion of an erbium salt into porous silicon formed by anodic etching of Si in hydrofluoric acid. Densification of the porous Si layers through high temperature oxidation after erbium diffusion forms erbium-doped SiO2 layers.

Insulating and Breakdown Characteristics of Low Temperature GaAs

1991 ◽  
Vol 241 ◽  
Author(s):  
H. L. Grubin ◽  
J. P. Kreskovsky ◽  
R. Levy
Keyword(s):  
Numerical Simulation ◽  
Low Temperature ◽  
Valence Band ◽  
Conduction Band ◽  
Electrical Characteristics ◽  
Simulation Techniques ◽  
Low Temperature Gaas ◽  
High Donor

ABSTRACTThe electrical characteristics of an N(LT)N structure are studied through implementation of numerical simulation techniques for the case of donor traps 0.83 ev below the conduction band and acceptor traps 0.3 ev above the valence band. The results show characteristics sensitive to the relative densities of the traps. In particular, high acceptor trap / low donor trap concentrations generally result in low breakdown voltages, whereas high acceptor / high donor concentrations result in higher breakdown voltages.

Characterization of Low Temperature SiNx Films for 3D/2.5D-IC TSV

2015 ◽  
Vol 135 (7) ◽  
pp. 733-738 ◽  
Author(s):  
Yasushi Kobayashi ◽  
Yoshihiro Nakata ◽  
Tomoji Nakamura ◽  
Mayumi B. Takeyama ◽  
Masaru Sato ◽  
...  
Keyword(s):  
Low Temperature

Preparation and Characterization of Ag Nanoparticles on Porous Silicon for Photo Conversion

2019 ◽  
Vol 50 (3) ◽  
pp. 82-95
Author(s):  
RAFID SABBAR ZAMEL ◽  
BAN KHALID MOHAMMED ◽  
ALAULDEEN SALAH YASEEN ◽  
HAITHAM T. HUSSEIN ◽  
UDAY MUHSIN NAYEF
Keyword(s):  
Porous Silicon ◽  
Ag Nanoparticles
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