Properties of a-Si:H and a-SiGe:H Films Deposited by Photo-Assisted CVD

1986 ◽  
Vol 70 ◽  
Author(s):  
R. E. Rocheleau ◽  
S. C. Jackson. ◽  
S. S. Hegedus ◽  
B. N. Baron
Keyword(s):  
High Efficiency ◽  
Chemical Vapor ◽  
Photovoltaic Cell ◽  
Gas Flows ◽  
Long Term Stability ◽  
Improved Stability ◽  
Deposition Processes ◽  
P Type

ABSTRACTChemical vapor deposition techniques, in particular plasma enhanced CVD, have been used to produce high quality a-Si:H materials. Continuing research is directed toward increased device performance, improved stability, and translation of scale to commercial production. A part of this effort is the evaluation of alternate CVD techniques which in addition to providing technical options for high efficiency and long term stability are likely to lead to improved understanding of the relationships between deposition processes and material properties. A relatively new technique for depositing a-Si:H is photo-CVD which utilizes ultraviolet light to initiate the decomposition of silane or disilane. The best results from both materials properties and device efficiency points of view have been achieved using mercury sensitized photo-CVD. Recently, a 10.5% efficient a-Si:H p-i-n photovoltaic cell, fabricated by photo-CVD, was reported [1]. A limitation in photo-CVD has been preventing deposition on the UV transparent window. In this paper we describe a new photo-CVD reactor with a moveable UV-transparent Teflon film and secondary gas flows to eliminate window fouling. The deposition and opto-electronic characterization of intrinsic a-Si:H and a-SiGe:H and p-type a-SiC:H are described. Finally, preliminary results of p-i-n solar cells are presented.

Fabrication of Boron Compensated Hydrogenated Amorphous Silicon Films with Significantly Improved Stability Using Plasma Enhanced Chemical Vapor Deposition Technique

1995 ◽  
Vol 377 ◽  
Author(s):  
Mohan K. Bhan
Keyword(s):  
Chemical Vapor ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Vapor Deposition Technique ◽  
Improved Stability ◽  
Donor Acceptor ◽  
B Doping ◽  
The Stability

ABSTRACTWe have systematically investigated the effects of addition of sub-ppm levels of boron on the stability of a-Si:H films and p-i-n devices, deposited by PE-CVD technique. The films thus produced with appropriate amounts of boron, show a significant improvement in stability, when soaked under both AM 1.5 (short-term) as well as 10×sun (long-term) illumination conditions. The opto-electronic properties of the films are quite respectable It is concluded that boron compensates the native impurities by forming donor-acceptor pairs, which reduces the “fast” defects and hence the initial degradation of the films. It is also speculated that boron may also be improving the short-term stability, by reducing the recombination of light generated electrons and holes, by converting D° into D+ states. The long-term stability appears to get affected by hydrogen dilution which seems to reduce the amount of “slow” defects. As a result of B doping of i-layer, the initial conversion efficiency of the devices decreases. It is presumed that our devices may contain an enhanced level of boron impurity, than expected, making them as worse material and to degrade less.

A p-Type PbS Quantum Dot Ink with Improved Stability for Solution Processable Optoelectronics

2021 ◽  
Author(s):  
Fiaz Ahmed ◽  
John Hardin Dunlap ◽  
Perry J. Pellechia ◽  
Andrew Greytak
Keyword(s):  
Quantum Dot ◽  
Ligand Exchange ◽  
Chemical Characterization ◽  
Single Step ◽  
Improved Stability ◽  
Solution Processable ◽  
P Type ◽  
Pbs Quantum Dot

A highly stable p-type PbS-QDs ink is prepared using a single-step biphasic ligand exchange route, overcoming instability encountered in previous reports. Chemical characterization of the ink reveals 3-mercaptopriopionic acid (MPA)...

Enhanced stability of conductive polyacetylene in ladder-like surface-grafted brushes

2016 ◽  
Vol 7 (36) ◽  
pp. 5664-5670 ◽  
Author(s):  
Michał Szuwarzyński ◽  
Karol Wolski ◽  
Szczepan Zapotoczny
Keyword(s):  
Term Stability ◽  
Long Term Stability ◽  
Enhanced Stability

Formation and characterization of polyacetylene-based brushes that exhibit exceptional long term stability in air is presented here.

Vacuum-process-based dry transfer of active layer with solvent additive for efficient organic photovoltaic devices

2017 ◽  
Vol 5 (5) ◽  
pp. 1106-1112 ◽  
Author(s):  
Jong Hwa Lee ◽  
Kang Min Kim ◽  
Woongsik Jang ◽  
Sunyong Ahn ◽  
Young Yun Kim ◽  
...  
Keyword(s):  
Active Layer ◽  
Photovoltaic Cell ◽  
Cell Performance ◽  
Organic Photovoltaic ◽  
Photovoltaic Devices ◽  
Organic Photovoltaic Devices ◽  
Organic Photovoltaic Cell ◽  
Long Term Stability ◽  
Solvent Additive

PTB7:PC71BM-based organic photovoltaic cell with solvent additive fabricated by transferring a BHJ layer via stamping transfer. This photovoltaic cell exhibited enhanced long-term stability and similar cell performance as compared with those of the spin-coated cells.

AlxGa1-xN-Based Materials and Heterostructures

1996 ◽  
Vol 449 ◽  
Author(s):  
P. Kung ◽  
A. Saxler ◽  
D. Walker ◽  
X. Zhang ◽  
R. Lavado ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Bragg Reflectors ◽  
X Ray Diffraction ◽  
Chemical Vapor Deposition Growth ◽  
X Ray ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Dimensional Electron Gas ◽  
P Type

ABSTRACTWe present the metalorganic chemical vapor deposition growth, n-type and p-type doping and characterization of AlxGa1-xN alloys on sapphire substrates. We report the fabrication of Bragg reflectors and the demonstration of two dimensional electron gas structures using AlxGa1-xN high quality films. We report the structural characterization of the AlxGa1-xN / GaN multilayer structures and superlattices through X-ray diffraction and transmission electron microscopy. A density of screw and mixed threading dislocations as low as 107 cm-2 was estimated in AlxGa1-xN / GaN structures. The realization of AlxGa1-xN based UV photodetectors with tailored cut-off wavelengths from 365 to 200 nm are presented.

scholarly journals One-step synthesis of carbon-supported electrocatalysts

2020 ◽  
Vol 11 ◽  
pp. 1419-1431
Author(s):  
Sebastian Tigges ◽  
Nicolas Wöhrl ◽  
Ivan Radev ◽  
Ulrich Hagemann ◽  
Markus Heidelmann ◽  
...  
Keyword(s):  
Hybrid Material ◽  
Chemical Vapor ◽  
Narrow Particle Size Distribution ◽  
Long Term Stability ◽  
Operational Lifetime ◽  
Metal Acetylacetonate ◽  
One Step ◽  
Supported Electrocatalysts ◽  
Platinum Loading

Cost-efficiency, durability, and reliability of catalysts, as well as their operational lifetime, are the main challenges in chemical energy conversion. Here, we present a novel, one-step approach for the synthesis of Pt/C hybrid material by plasma-enhanced chemical vapor deposition (PE-CVD). The platinum loading, degree of oxidation, and the very narrow particle size distribution are precisely adjusted in the Pt/C hybrid material due to the simultaneous deposition of platinum and carbon during the process. The as-synthesized Pt/C hybrid materials are promising electrocatalysts for use in fuel cell applications as they show significantly improved electrochemical long-term stability compared to the industrial standard HiSPEC 4000. The PE-CVD process is furthermore expected to be extendable to the general deposition of metal-containing carbon materials from other commercially available metal acetylacetonate precursors.

scholarly journals Rational design of MgF2 catalysts with long-term stability for the dehydrofluorination of 1,1-difluoroethane (HFC-152a)

RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23744-23751 ◽  
Author(s):  
Haodong Tang ◽  
Mingming Dang ◽  
Yuzhen Li ◽  
Lichun Li ◽  
Wenfeng Han ◽  
...  
Keyword(s):  
Rational Design ◽  
Sol Gel ◽  
Hard Template ◽  
Term Stability ◽  
Long Term Stability ◽  
Improved Stability ◽  
Hfc 152A ◽  
Template Methods

In this study, sol–gel, precipitation and hard-template methods were applied to synthesize MgF2 catalysts with improved stability towards dehydrofluorination of hydrofluorocarbons and MgF2-T catalysts demonstrated superior long-term stability.

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