scholarly journals First observation of aromatic bond density: a 'forgotten' paper by Rosalind E. Franklin

2021 ◽  
Vol 77 (a1) ◽  
pp. a23-a23
Author(s):  
Alexander Nazarenko
Keyword(s):  
Bond Density

Control of dihydride bond density in reactive sputtered amorphous silicon

1979 ◽  
Vol 50 (11) ◽  
pp. 7034-7038 ◽  
Author(s):  
F. R. Jeffrey ◽  
H. R. Shanks ◽  
G. C. Danielson
Keyword(s):  
Amorphous Silicon ◽  
Bond Density

Simultaneous Relaxation of Network and Defects in Silicon-Implanted a-Si:H

1995 ◽  
Vol 377 ◽  
Author(s):  
J. Nakata ◽  
S. Sherman ◽  
S. Wagner ◽  
P. A. Stolk ◽  
J. M. Poate
Keyword(s):  
Electronic Transport ◽  
Annealing Temperature ◽  
Urbach Energy ◽  
Defect Density ◽  
Dark Conductivity ◽  
Equilibrium Theory ◽  
Hopping Conduction ◽  
Dangling Bond ◽  
Bond Density ◽  
Additional Illumination

ABSTRACTWe report extensive optical and electronic transport data on silicon-implanted a-Si:H, annealed in steps in the dark or with additional illumination. All measured properties relax gradually with increasing annealing temperature. The dark conductivity of the as-implanted film is dominated by hopping conduction via midgap defects. This channel is pinched off during the initial stages of annealing. The midgap defect density and the Urbach energy follow an annealing path that agrees qualitatively with the trajectory postulated by the equilibrium theory of the dangling-bond density. Therefore, the silicon network and the defect density equilibrate continuously during network relaxation.

Hydrogenated Amorphous Silicon Films Prepared by Mercury Sensitized Photochemical Vapor Deposition

1989 ◽  
Vol 149 ◽  
Author(s):  
Takaaki Kamimura ◽  
Hidetoshi Nozaki ◽  
Naoshi Sakuma ◽  
Mitsuo Nakajima ◽  
Hiroshi Ito
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Hydrogenated Amorphous Silicon ◽  
Gas Phase Reactions ◽  
Bond Density ◽  
Hydrogen Elimination ◽  
Photochemical Vapor Deposition ◽  
The Relationship ◽  
Hydrogenated Amorphous ◽  
Activation Type

ABSTRACTHydrogenated amorphous silicon (a-Si:H) films were prepared by mercury photosensitized decomposition of silane using a low-pressure mercury lamp. The deposition rate showed an activation type for substrate temperature (the activation energy: 0.13 eV), because the deposition rate would be determined by the rate of hydrogen elimination from the hydrogen saturated surface. Moreover, the relationship was found between the Si-H2 bond density in a- Si:H films and the gas phase reactions.

Fabrication of Device-Quality Wide-Gap a-Si:H Films at Very Low Substrate Temperatures

1990 ◽  
Vol 192 ◽  
Author(s):  
Yoshihiro Hishikawa ◽  
Sadaji Tsuge ◽  
Noboru Nakamura ◽  
Shinya Tsuda ◽  
Shoichi Nakano ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Light Exposure ◽  
Rf Plasma ◽  
Plasma Parameters ◽  
Solar Cell Performance ◽  
Capacitively Coupled ◽  
Bond Density ◽  
Deposition Parameters ◽  
Wide Gap ◽  
Substrate Temperatures

ABSTRACTWide-gap a-Si:H films with device quality (Tauc’s optical gap > 1.9eV, σph under AMI.5, 100mW/cm2 illumination ≥ 10−5, Ω−1cm−1, a σph/σ a≥106) have been fabricated. These films are deposited at low substrtate temperatures (TS≤80°C ) either by diluting SiH4 with H2 or optimizing the plasma parameters in a capacitively–coupled RF plasma–CVD reactor. Reduction in the SiH2 bond density and the ESR spin density are also observed. In this study, good film quality is always accompanied by a small deposition rate. Furthermore, σph is nearly the same if the deposition rate and Ts is the same, regardless of other deposition parameters. This suggests that the surface reactions or structural relaxations at the film-growing surface can produce high–quality a–Si:H films even at low TsS, if the deposition rate is low. Results in thermal annealing, light exposure, and solar cell performance confirm that these films have device quality and wide bandgap.

Structure and Optical Properties of Porous Silicon Formed on Silicon Substrates Treated with Compression Plasma Flow

2015 ◽  
Vol 245 ◽  
pp. 49-54
Author(s):  
Mikhail Victorovich Bozhenko ◽  
Evgeniy Anatolievich Chusovitin ◽  
Nikolay Gennadievich Galkin ◽  
Evgeny Vladislavovich Pustovalov ◽  
Vladimir Vadimovich Tkachev ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Plasma Flow ◽  
Wavelength Region ◽  
Peak Position ◽  
Silicon Substrates ◽  
Intensity Increase ◽  
Long Wavelength ◽  
Bond Density ◽  
Compression Plasma Flow ◽  
Pl Intensity

Porous silicon layers were formed on the silicon substrates treated with compression plasma flow. Pores density and lateral size on substrates treated with plasma is by 25% more than that on untreated substrates. The intensity of the PL of the PS layers, formed on the plasma treated substrates (PT PS), is twice more than that of the PS layers, formed on untreated substrates. Three month exposure of normal PS and PT PS layers to the air leads to the PL intensity increase by 3 and 5.7 times, respectively, as well as to the peak position shifting towards long wavelength region by 3.1 nm, in the case of PT PS layer. The PL intensity increase is attributable to the reduction of the dangling bond density as a result of passivation by oxygen.

Correlation Between Freeze-In Temperature of Defect Density and Hydrogen Concentration in a-Si:H

1991 ◽  
Vol 219 ◽  
Author(s):  
X. Xu ◽  
M. Isomura ◽  
J. H. Yoon ◽  
S. Wagner ◽  
J. R. Abelson
Keyword(s):  
Hydrogen Concentration ◽  
Defect Density ◽  
Dangling Bond ◽  
Bond Density ◽  
Higher Temperature ◽  
Defect Densities

ABSTRACTWe measured the freeze-in temperature of the dangling-bond density in a-Si:H in nine samples with hydrogen concentrations ranging from 7.0 to 31 at.%. The measurements were made by determining the defect density of samples quenched from successively higher temperature. We determined the defect densities with the constant photoconductivity method. The freeze-in temperature is 211±10 °C, and is independent of hydrogen concentration.

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