Optical Emission Study of the Energy Levels of Ga-VACANCY/HYDROGEN Complexes in N and P-TYPE GaAs

1992 ◽  
Vol 262 ◽  
Author(s):  
A. Amore Bonapasta ◽  
B. Bonanni ◽  
M. Capizzi ◽  
L. Cherubini ◽  
V. Emiliani ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Energy Levels ◽  
Optical Emission ◽  
Shallow Donor ◽  
Equal Treatment ◽  
Present Observation ◽  
Emission Study ◽  
The Individual ◽  
P Type ◽  
Impurities And Defects

ABSTRACTThe formation of Ga-vacancy/hydrogen complexes in GaAs has been detected via photoluminescence measurements. Different degrees of hydrogénation can be achieved by low-energy H- or D-ion irradiation from a Kaufman source. The volume incorporation, for equal treatment, is dependent upon the density of impurities and defects where H can bind. In originally p-type MBE-GaAs, prolonged hydrogen treatments lead to the appearance of three emission structures in the range 1.15–1.34 eV. The results are explained in terms of transitions to different states of charge of gallium vacancies trapping one or more H-atoms, the activity of the individual states being dependent upon the H-dose and the nature of the laser excitation. The model is supported by comparison with the changes in the Ga-vacancy/donor emission band in degenerate n-type samples, as it evolves, from the virgin condition, through hydrogenation. The present observation provides also valid support to the creation, in p-type material, of a semi-shallow donor associated to H trapped along the As-Ga bond, in the immediate neighborhood of the gallium vacancy.

scholarly journals Optimization of Sb2S3 Nanocrystal Concentrations in P3HT: PCBM Layers to Improve the Performance of Polymer Solar Cells

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2152
Author(s):  
E. M. Mkawi ◽  
Y. Al-Hadeethi ◽  
R. S. Bazuhair ◽  
A. S. Yousef ◽  
E. Shalaan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Doping Concentration ◽  
Polymer Solar Cells ◽  
Energy Levels ◽  
Acid Methyl Ester ◽  
Visible Absorption ◽  
Block Polymer ◽  
Coating Method ◽  
Electronic Parameters ◽  
P Type

In this study, polymer solar cells were synthesized by adding Sb2S3 nanocrystals (NCs) to thin blended films with polymer poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) as the p-type material prepared via the spin-coating method. The purpose of this study is to investigate the dependence of polymer solar cells’ performance on the concentration of Sb2S3 nanocrystals. The effect of the Sb2S3 nanocrystal concentrations (0.01, 0.02, 0.03, and 0.04 mg/mL) in the polymer’s active layer was determined using different characterization techniques. X-ray diffraction (XRD) displayed doped ratio dependences of P3HT crystallite orientations of P3HT crystallites inside a block polymer film. Introducing Sb2S3 NCs increased the light harvesting and regulated the energy levels, improving the electronic parameters. Considerable photoluminescence quenching was observed due to additional excited electron pathways through the Sb2S3 NCs. A UV–visible absorption spectra measurement showed the relationship between the optoelectronic properties and improved surface morphology, and this enhancement was detected by a red shift in the absorption spectrum. The absorber layer’s doping concentration played a definitive role in improving the device’s performance. Using a 0.04 mg/mL doping concentration, a solar cell device with a glass /ITO/PEDOT:PSS/P3HT-PCBM: Sb2S3:NC/MoO3/Ag structure achieved a maximum power conversion efficiency of 2.72%. These Sb2S3 NCs obtained by solvothermal fabrication blended with a P3HT: PCBM polymer, would pave the way for a more effective design of organic photovoltaic devices.

The KATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers

2011 ◽  
Vol 301 (4) ◽  
pp. R916-R925 ◽  
Author(s):  
Krystyna Banas ◽  
Charlene Clow ◽  
Bernard J. Jasmin ◽  
Jean-Marc Renaud
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Fiber Type ◽  
Energy Levels ◽  
Muscle Fibers ◽  
Metabolic Stress ◽  
Oxidative Capacity ◽  
Fiber Types ◽  
Fiber Damage ◽  
The Individual

It has long been suggested that in skeletal muscle, the ATP-sensitive K+ channel (KATP) channel is important in protecting energy levels and that abolishing its activity causes fiber damage and severely impairs function. The responses to a lack of KATP channel activity vary between muscles and fibers, with the severity of the impairment being the highest in the most glycolytic muscle fibers. Furthermore, glycolytic muscle fibers are also expected to face metabolic stress more often than oxidative ones. The objective of this study was to determine whether the t-tubular KATP channel content differs between muscles and fiber types. KATP channel content was estimated using a semiquantitative immunofluorescence approach by staining cross sections from soleus, extensor digitorum longus (EDL), and flexor digitorum brevis (FDB) muscles with anti-Kir6.2 antibody. Fiber types were determined using serial cross sections stained with specific antimyosin I, IIA, IIB, and IIX antibodies. Changes in Kir6.2 content were compared with changes in CaV1.1 content, as this Ca2+ channel is responsible for triggering Ca2+ release from sarcoplasmic reticulum. The Kir6.2 content was the lowest in the oxidative soleus and the highest in the glycolytic EDL and FDB. At the individual fiber level, the Kir6.2 content within a muscle was in the order of type IIB > IIX > IIA ≥ I. Interestingly, the Kir6.2 content for a given fiber type was significantly different between soleus, EDL, and FDB, and highest in FDB. Correlations of relative fluorescence intensities from the Kir6.2 and CaV1.1 antibodies were significant for all three muscles. However, the variability in content between the three muscles or individual fibers was much greater for Kir6.2 than for CaV1.1. It is suggested that the t-tubular KATP channel content increases as the glycolytic capacity increases and as the oxidative capacity decreases and that the expression of KATP channels may be linked to how often muscles/fibers face metabolic stress.

scholarly journals Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2592 ◽  
Author(s):  
Funeka Matebese ◽  
Raymond Taziwa ◽  
Dorcas Mutukwa
Keyword(s):  
Solar Cells ◽  
Energy Levels ◽  
Perovskite Solar Cells ◽  
Hole Mobility ◽  
Cost Effective ◽  
Vital Role ◽  
Hole Transport ◽  
Recombination Processes ◽  
Short Synthesis ◽  
P Type

P-type wide bandgap semiconductor materials such as CuI, NiO, Cu2O and CuSCN are currently undergoing intense research as viable alternative hole transport materials (HTMs) to the spiro-OMeTAD in perovskite solar cells (PSCs). Despite 23.3% efficiency of PSCs, there are still a number of issues in addition to the toxicology of Pb such as instability and high-cost of the current HTM that needs to be urgently addressed. To that end, copper thiocyanate (CuSCN) HTMs in addition to robustness have high stability, high hole mobility, and suitable energy levels as compared to spiro-OMeTAD HTM. CuSCN HTM layer use affordable materials, require short synthesis routes, require simple synthetic techniques such as spin-coating and doctor-blading, thus offer a viable way of developing cost-effective PSCs. HTMs play a vital role in PSCs as they can enhance the performance of a device by reducing charge recombination processes. In this review paper, we report on the current progress of CuSCN HTMs that have been reported to date in PSCs. CuSCN HTMs have shown enhanced stability when exposed to weather elements as the solar devices retained their initial efficiency by a greater percentage. The efficiency reported to date is greater than 20% and has a potential of increasing, as well as maintaining thermal stability.

scholarly journals Влияние одноосной деформации в направлении [110] на релаксацию состояний мелких доноров мышьяка в германии

2020 ◽  
Vol 54 (9) ◽  
pp. 918
Author(s):  
В.В. Цыпленков ◽  
В.Н. Шастин
Keyword(s):  
Energy Levels ◽  
Optical Excitation ◽  
Uniaxial Stress ◽  
Shallow Donor ◽  
Stimulated Emission ◽  
Relaxation Rates ◽  
Emission Frequency ◽  
Donor States ◽  
Uniaxial Compressive Stress ◽  
Intracenter Transitions

Analysis of acoustical phonon assisted relaxation rates of arsenic donor states has been carried out in depends on uniaxial compressive stress of crystal along [110] direction under low temperature (< 10 K). As shown, under optical excitation the inversion population of donor energy levels is formed that depends on deformation of crystal. This give grounds to suppose that stimulated emission on arsenic shallow donor intracenter transitions in THz range is possible under optical excitation. As shown, uniaxial stress along [110] direction can result to switch laser transition and stimulated emission frequency

scholarly journals Spin-0 system of DKP equation in the background of a flat class of Gödel-type spacetime

2019 ◽  
Vol 35 (07) ◽  
pp. 2050031 ◽  
Author(s):  
Faizuddin Ahmed ◽  
Hassan Hassanabadi
Keyword(s):  
Energy Levels ◽  
Wave Functions ◽  
Dkp Equation ◽  
Free Particles ◽  
The Individual

In this paper, we investigate the Duffin–Kemmer–Petiau (DKP) equation for spin-0 system of charge-free particles in the background of a flat class of Gödel-type spacetimes, and evaluate the individual energy levels and corresponding wave functions in detail.

scholarly journals Colliding Stellar Winds in O-type Close Binary Systems

1992 ◽  
Vol 135 ◽  
pp. 146-148
Author(s):  
D.R. Gies ◽  
M.S. Wiggs
Keyword(s):  
Binary Systems ◽  
Optical Emission ◽  
Emission Lines ◽  
Optical Observations ◽  
Close Binary ◽  
High Dispersion ◽  
Stellar Winds ◽  
Close Binary Systems ◽  
Circumstellar Gas ◽  
The Individual

In close binary systems of O-type stars, the individual stellar winds will collide between the stars to form shock fronts (Stevens et al. 1992). Binaries with equally luminous stars will have winds of comparable strength, and the shock will occur near the mid-plane between the stars, but in binaries of unequal luminosity, the interaction will occur along a bow shock wrapped around the star with the weaker wind. The presence of the shock region can be detected through excess X-ray emission (Chlebowski & Garmany 1990), and orbital phase-related variations in the UV P Cygni lines (Shore & Brown 1988) and optical emission lines (formed in high density regions of circumstellar gas).We have begun a search for colliding winds through a study of the optical emission lines and UV P Cygni lines in four massive binaries, AO Cas (Gies & Wiggs 1991), Plaskett’s star = HD 47129 (Wiggs & Gies 1992), 29 UW CMa and ι Ori. The optical observations consist of high S/N spectra of the Hα and He I λ6678 region obtained with the University of Texas McDonald Observatory 2.1-m telescope and coudé Reticon system. The UV observations were culled from archival IUE high dispersion spectra of several P Cygni features (N V λ1240, Si IV λ1400, C IV λ1550).

scholarly journals Gender and Development: A Study of Feminist Theories

2020 ◽  
Vol 7 (2) ◽  
pp. 20
Author(s):  
Farhana Haque
Keyword(s):  
Radical Feminism ◽  
Equal Treatment ◽  
Gender And Development ◽  
Human Beings ◽  
Men And Women ◽  
Historical Perspectives ◽  
Different Types ◽  
Feminist Theories ◽  
Race Ethnicity ◽  
The Individual

The term feminism derived from the notion to establish women’s right equal like men. It refers to the ideology that men and women should be treated equally both in the sections of politics and morality. Feminism means to create a scope to women to raise their voice against men regarding the matter of equality and as a result feminism does frequently linked towards different types of motions since last two centuries and performed to execute the concept of parity through implanting it throughout the culture. There are several other opinions and ideologies by different feminists regarding the term equality. The individual feminists said equality means equal treatment and that should be under the laws about homage the person and possession like the entire human beings without paying attention towards the secondary characteristics like sex, race, ethnicity. The school of feminism which is radical feminism. According to them parity means socioeconomic parity where power and wealth should be re-established by law through the society. Therefore from the historical perspectives advantages of men become deleted.

Attempts to p-Dope Ultrananocrystalline Diamond Films in a Hot Filament Reactor

2006 ◽  
Vol 956 ◽  
Author(s):  
Paul William May ◽  
Matthew Hannaway
Keyword(s):  
Vapour Deposition ◽  
Film Growth ◽  
Substrate Surface ◽  
Diamond Films ◽  
Chemical Vapour ◽  
Grain Sizes ◽  
Ultrananocrystalline Diamond ◽  
The Individual ◽  
P Type ◽  
Hot Filament

ABSTRACTUltrananocrystalline diamond (UNCD) films have been deposited using hot filament chemical vapour deposition using Ar/CH4/H2 gas mixtures plus additions of B2H6 in an attempt to make p-type semiconducting films. With increasing additions of B2H6 from 0 to 40,000 ppm with respect to C, the film growth rate was found to decrease substantially, whilst the individual grain sizes increased from nm to μm. With 40,000 ppm of B2H6, crystals of boric oxide were found on the substrate surface, which slowly hydrolysed to boric acid on exposure to air. These results are rationalised using a model for UNCD growth based on competition for surface radical sites between CH3 and C atoms.

Electrical isolation of p-type GaAsN epitaxial layers by ion irradiation

2002 ◽  
Vol 744 ◽  
Author(s):  
Q. Gao ◽  
J. Muller ◽  
P. N. K. Deenapanray ◽  
H. H. Tan ◽  
C. Jagadish
Keyword(s):  
Ion Irradiation ◽  
Free Carrier ◽  
Conductive Layer ◽  
Electrical Isolation ◽  
Atomic Displacements ◽  
Carrier Traps ◽  
The Stability ◽  
P Type ◽  
Accumulated Dose ◽  
Density Results

ABSTRACTThe evolution of sheet resistance (Rs) of p-type conductive GaAs(1-x)Nx epilayers (x = 0.6%, 1.4%, and 2.3%) exposed to MeV 1H+, 7Li+, 12C+, and 16O+ ions and the stability of the formed electrical isolation during post-irradiation annealing were investigated. Results show that the threshold dose (Dth) to convert a conductive layer to highly resistive one close-to-linearly depends on original free carrier concentration and inversely depends on the number of irradiation-generated atomic displacements, and is independent of the nitrogen content in GaAsN layers. Increasing beam flux of 12C+ results in a lower Dth, whereas 1H+ beam flux does not affect it, showing the influence of collision cascade density. Results also show that irrespectively of the ion mass, the stability of electrical isolation formed in GaAsN is dependent on the ratio of the concentration of irradiation-created carrier traps to Dth. The electrical isolation can be preserved up to 550°C when the accumulated dose (D) is greater than 3.3 Dth.

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