Numerical Simulation and Experimental Investigation of the Time-Of-Flight Technique Applied to a-Si:H/a-SiGe:H-Heterojunctions

1993 ◽  
Vol 297 ◽  
Author(s):  
Rudi Brüggemann ◽  
Norbert Bernhard ◽  
Charles Main ◽  
Gottfried H. Bauer
Keyword(s):  
Numerical Simulation ◽  
Experimental Investigation ◽  
Room Temperature ◽  
Drift Mobility ◽  
Electron Current ◽  
Pronounced Difference ◽  
Low Bandgap ◽  
Direction Of Movement ◽  
Current Transients

We report on a comparative study, employing the TOF-technique for the characterization of the properties of a-Si:H/a-SiGe:H-heterojunctions. Both the simulated and experimental electron current transients exhibit a pronounced difference depending on the direction of movement of the excess carriers (from the a-Si:H into the a-SiGe:H or vice versa). For the movement from the low bandgap a-SiGe:H into the a-Si:H we find a char¬acteristic increase in the transient current at room temperature, which, as the simulation can reveal, is attributed to the higher drift mobility in the a-Si:H. A drop in the current is observed when the direction for the transit is from a-Si:H to a-SiGe:H. The post-transit behaviour is dominated by the large amount of trapped carriers which remain on the SiGe side of the sample. The situation for a high barrier between a-Si:H and a-SiC:H and the influence of various parameters on the shape of the current transient are discussed.

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

scholarly journals Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13245-13255
Author(s):  
Mehdi Davoodi ◽  
Fatemeh Davar ◽  
Mohammad R. Rezayat ◽  
Mohammad T. Jafari ◽  
Mehdi Bazarganipour ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnesium Aluminate ◽  
Synthesis And Characterization ◽  
Magnesium Aluminate Spinel ◽  
Adsorption Behaviour ◽  
Zeolitic Imidazolate Framework ◽  
Simple Method

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios.

Experimental investigation on the characterization of self-starting capability of a 3-bladed Savonius hydrokinetic turbine using deflector plates

2021 ◽  
Vol 228 ◽  
pp. 108950
Author(s):  
Mohd Badrul Salleh ◽  
Noorfazreena M. Kamaruddin ◽  
Zulfaa Mohamed-Kassim ◽  
Elmi Abu Bakar
Keyword(s):  
Experimental Investigation ◽  
Hydrokinetic Turbine

scholarly journals The Mutant Phenotype Associated With P-Element Alleles of the vestigial Locus in Drosophila melanogaster May Be Caused by a Readthrough Transcript Initiated at the P-Element Promoter

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1665-1672 ◽  
Author(s):  
Ross B Hodgetts ◽  
Sandra L O'Keefe
Keyword(s):  
Rna Secondary Structure ◽  
Insertion Site ◽  
Large Body ◽  
P Element ◽  
Wild Type ◽  
Subtle Difference ◽  
Pronounced Difference ◽  
Internal Repeat ◽  
Mutant Phenotypes

Abstract We report here the isolation of a new P-element-induced allele of the vestigial locus vg2a33, the molecular characterization of which allows us to propose a unifying explanation of the phenotypes of the large number of vestigial P-element alleles that now exists. The first P-element allele of vestigial to be isolated was vg21, which results in a very weak mutant wing phenotype that is suppressed in the P cytotype. By destabilizing vg2a33 in a dysgenic cross, we isolated the vg2a33 allele, which exhibits a moderate mutant wing phenotype and is not suppressed by the P cytotype. The new allele is characterized by a 46-bp deletion that removes the 3′-proximal copy of the 11-bp internal repeat from the P element of vg21. To understand how this subtle difference between the two alleles leads to a rather pronounced difference in their phenotypes, we mapped both the vg and P-element transcription units present in wild type and mutants. Using both 5′-RACE and S1 protection, we found that P-element transcription is initiated 19 bp farther upstream than previously thought. Using primer extension, the start of vg transcription was determined to lie 435 bp upstream of the longest cDNA recovered to date and upstream of the P-element insertion site. Our discovery that the P element is situated within the first vg exon has prompted a reassessment of the large body of genetic data on a series of alleles derived from vg21. Our current hypothesis to explain the degree of variation in the mutant phenotypes and their response to the P repressor invokes a critical RNA secondary structure in the vg transcript, the formation of which is hindered by a readthrough transcript initiated at the P-element promoter.

Sign in / Sign up

Export Citation Format

Share Document