Density-of-States Distribution In Disilane LPCVD Deposited Amorphous Silicon as Determinated By SCLC

1986 ◽  
Vol 70 ◽  
Author(s):  
C. Manfredotti ◽  
G. Gervino ◽  
L. Montaldi ◽  
R. Varesio ◽  
A. Zanini ◽  
...  
Keyword(s):  
Fermi Level ◽  
Amorphous Silicon ◽  
Density Of States ◽  
Hydrogen Content ◽  
Deposition Temperature ◽  
Direct Method ◽  
A Direct Method ◽  
Deposited Films

ABSTRACTI-V characteristics have been measured in a-Si:H films deposited from Si2 H6 by LPCVD and have been analyzed according to a direct method. DOS distribution is thickness-dependent, similarly to what has been found on SiH deposited films, with values at Fermi level ranging from below 1016 cm-3 eV-1 up to 1018 cm-3 eV-1. Deposition temperature, at least in the interval 450 - 500°C, does not seem to affect DOS distribution. Hydrogen content is pratically constant in all the films. The only possible conclusion is that only thickness influences DOS distribution and that only for thickness larger than 0.8 μm it is possible to get densities at Fermi level below 1016 cm-3 eV-1.

Toward the Elimination of Light-Induced Degradation of Amorphous Si by Fluorine Incorporation

1992 ◽  
Vol 258 ◽  
Author(s):  
X. Deng ◽  
E. Mytilineou ◽  
R. T. Young ◽  
S. R. Ovshinsky
Keyword(s):  
Glow Discharge ◽  
Amorphous Silicon ◽  
Density Of States ◽  
Deposition Temperature ◽  
Gas Mixture ◽  
Dangling Bonds ◽  
Material Stability ◽  
Saturated State ◽  
High Deposition Temperature ◽  
Amorphous Si

ABSTRACTWe report on evidence that fluorine, properly incorporated into a-Si, replaces weakly bonded hydrogen and improves the material stability under light soaking. Our fluorinated amorphous silicon (a-Si:H:F) is made by if glow discharge at high deposition temperatures up to 430 C from a gas mixture of SiH4 or Si2H6 and F2. These a-Si:H:F films show much lower density of states in the light soaking saturated state than device quality a-Si:H prepared in the same deposition system. It is evident from our results that fluorine incorporated into the network at such high deposition temperature makes for a new configuration which minimizes dangling bonds and other defects.

scholarly journals Plastic waste to fuels by hydrocracking at mild conditions

2021 ◽  
Vol 7 (17) ◽  
pp. eabf8283
Author(s):  
Sibao Liu ◽  
Pavel A. Kots ◽  
Brandon C. Vance ◽  
Andrew Danielson ◽  
Dionisios G. Vlachos
Keyword(s):  
Direct Method ◽  
Acid Sites ◽  
Liquid Fuels ◽  
High Yield ◽  
Tandem Catalysis ◽  
Hy Zeolite ◽  
Environmental Threat ◽  
Single Use ◽  
Initial Activation ◽  
A Direct Method

Single-use plastics impose an enormous environmental threat, but their recycling, especially of polyolefins, has been proven challenging. We report a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons, with high yield up to 85% over Pt/WO3/ZrO2 and HY zeolite in hydrogen at temperatures as low as 225°C. The process proceeds via tandem catalysis with initial activation of the polymer primarily over Pt, with subsequent cracking over the acid sites of WO3/ZrO2 and HY zeolite, isomerization over WO3/ZrO2 sites, and hydrogenation of olefin intermediates over Pt. The process can be tuned to convert different common plastic wastes, including low- and high-density polyethylene, polypropylene, polystyrene, everyday polyethylene bottles and bags, and composite plastics to desirable fuels and light lubricants.

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