scholarly journals Reciprocal Space Analysis of the Microstructure of Luminescent and Nonluminescent Porous Silicon Films

1994 ◽  
Vol 358 ◽  
Author(s):  
S.R. Lee ◽  
J.C. Barbour ◽  
J.W. Medernach ◽  
J.O. Stevenson ◽  
J.S. Custer
Keyword(s):  
Porous Silicon ◽  
Space Structure ◽  
Reciprocal Space ◽  
Silicon Films ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Crystalline Materials ◽  
X Ray ◽  
Space Analysis ◽  
Spatially Correlated

ABSTRACTThe microstructure of anodically prepared porous silicon films was determined using a novel x-ray diffraction technique. This technique uses double-crystal diffractometry combined with position-sensitive x-ray detection to efficiently and quantitatively image the reciprocal space structure of crystalline materials. Reciprocal space analysis of newly prepared, as well as aged, p+ porous silicon films showed that these films exhibit a very broad range of crystallinity. This material appears to range in structure from a strained, single-crystal, sponge-like material exhibiting long-range coherency to isolated, dilated nanocrystals embedded in an amorphous matrix. Reciprocal space analysis of n+ and p+ porous silicon showed these materials are strained single-crystals with a spatially-correlated array of vertical pores. The vertical pores in these crystals may be surrounded by nanoporous or nanocrystalline domains as small as a few nm in size which produce diffuse diffraction indicating their presence. The photoluminescence of these films was examined using 488 nm Ar laser excitation in order to search for possible correlations between photoluminescent intensity and crystalline microstructure.

High Resolution Digital X-Ray Rocking Curve Topography

1986 ◽  
Vol 30 ◽  
pp. 527-535 ◽  
Author(s):  
T.S. Ananthanarayanan ◽  
W.E. Mayo ◽  
R.G. Rosemeier
Keyword(s):  
Defect Structure ◽  
Semiconductor Device ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
Crystalline Materials ◽  
Digital Implementation ◽  
X Ray ◽  
Rapid Characterization ◽  
Non Destructive

AbstractThis study presents a unique and novel enhancement of the double crystal diffractometer which allows topographic mapping of X-ray diffraction rocking curve half widths at about 100-150μm spatial resolution. This technique can be very effectively utilized to map micro-lattice strain fields in crystalline materials. The current focus will be on the application of a recently developed digital implementation for the rapid characterization of defect structure and distribution in various semiconductor materials.Digital Automated Rocking Curve (DARC) topography has been successfully applied for characterizing defect structure in materials such as: GaAs, Si, AlGaAs, HgMnTe, HgCdTe, CdTe, Al, Inconnel, Steels, BaF2 PbS, PbSe, etc. The non-intrusive (non- contact & non-destructive) nature of the DARC technique allows its use in studing several phenomena such as corrosion fatigue, recrystallization, grain growth, etc., in situ. DARC topography has been used for isolating regions of non-uniform dislocation density on various materials. It is envisioned that this highly sophisticated, yet simple to operate, system will improve semiconductor-device yield significantly.The high strain sensitivity of the technique results from combination of the highly monochromated and collimated X-ray probe beani, the State of the art linear position-sensitive detector (LPSD) and the high-precision specimen goniometer.

scholarly journals INVESTIGATION OF LATTICE DEFORMATION OF POROUS SILICON FILMS BY X-RAY DOUBLE CRYSTAL DIFFRACTION

1993 ◽  
Vol 42 (6) ◽  
pp. 954
Author(s):  
HE XIAN-CHANG ◽  
WU ZI-QIN ◽  
ZHAO TE-XIU ◽  
Lü ZHI-HUI ◽  
WANG XIAO-PING ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Silicon Films ◽  
Lattice Deformation ◽  
Double Crystal ◽  
X Ray

Rapid Thermal Oxidation for Passivation of Porous Silicon

1994 ◽  
Vol 342 ◽  
Author(s):  
I. BÁrsony ◽  
J.G.E. Klappe ◽  
É. Vázsonyi ◽  
T. Lohner ◽  
M. Fried
Keyword(s):  
Porous Silicon ◽  
Mechanical Stability ◽  
Porous Substrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Tetragonal Lattice ◽  
Optical Heating ◽  
Vertical Inhomogeneity ◽  
Highly Porous

ABSTRACTChemical and mechanical stability of porous silicon layers (PSL) is the prerequisite of any active (luminescent) or passive (e.g. porous substrate) integrated applications. In this work X-ray diffraction (XRD) was used to analyze quantitatively the strain distribution obtained in different morphology PSL that were prepared on (100) p and p+Si substrates. Tetragonal lattice constant distortion can be as high as 1.4% in highly porous “as-prepared” samples. Incoherent optical heating RTO is governed by the absorption in the oxidized specimen. PSL show vertical inhomogeneity according to interpretation of spectroscopic ellipsometry (SE) data. Oxygen incorporation during RTO is controlled by specific surface (in p+ proportional, in p inversely proportional with porosity), while the developing compressive stress depends on pore size, and decreases with porosity in both morphologies.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

Applications of High-Resolution Powder X-Ray Diffraction

2007 ◽  
Vol 130 ◽  
pp. 7-14 ◽  
Author(s):  
Andrew N. Fitch
Keyword(s):  
High Resolution ◽  
Synchrotron Radiation ◽  
Powder Diffraction ◽  
X Rays ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Structural Characterisation ◽  
Pdf Analysis

The highly-collimated, intense X-rays produced by a synchrotron radiation source can be harnessed to build high-resolution powder diffraction instruments with a wide variety of applications. The general advantages of using synchrotron radiation for powder diffraction are discussed and illustrated with reference to the structural characterisation of crystalline materials, atomic PDF analysis, in-situ and high-throughput studies where the structure is evolving between successive scans, and the measurement of residual strain in engineering components.

A simple and low-cost solution for the automation of X-ray powder diffractometers with chart recorder output

2006 ◽  
Vol 39 (4) ◽  
pp. 626-629
Author(s):  
M. Jayaprakasan ◽  
V. Kannan ◽  
P. Ramasamy
Keyword(s):  
Quantitative Analysis ◽  
Low Cost ◽  
Hard Copy ◽  
X Ray Diffraction ◽  
Raw Data ◽  
Crystalline Materials ◽  
X Ray ◽  
Strip Chart ◽  
Controlled Systems ◽  
Chart Recorder

X-ray powder diffraction is an established method for the qualitative identification of crystalline materials and their quantitative analysis. The new generation of X-ray diffraction systems are based on expensive digital/embedded control technology and computer interfaces. Yet many laboratories use conventional manual-controlled systems withXYstrip-chart recorders. Since the output spectrum is a strip chart (hard copy), raw data, essential for structural and qualitative analysis, are not readily available for further analysis. Upgrading to modern computerized diffractometers is very expensive. The proposed automation design described here is intended to enable the conventional diffractometer user to collect, store and analyze data quickly. The design also improves the resolution by five times compared with the conventional setup. For the automation, a PC add-on card has been designed to control and collect the timing and intensity counts from the conventional X-ray diffractometer, and suitable software has been developed to collect, process and present the X-ray diffraction data for both qualitative and quantitative analysis. Moreover, a major advantage of this design is that it does not warrant any physical modification of the hardware of the conventional setup; it is simply an extension to enhance the performance of collecting raw data with a higher resolution at desired intervals/timings.

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