PDF Publication Title:
Text from PDF Page: 017
characterization to aid understanding of the 85/85 test results. Work has been hampered by problems with the PECVD system, however, this project will be continued in the coming fiscal year. Based on the success of the XPS results, Surface Analysis project personnel will lead more of this work in the coming year. Complete experiments to quantify distributions of detrimental elements in recrystallized thin-film Si on foreign substrates: The original intent of this work was to study crystallization of hot-wire CVD a-Si:H on a variety of substrates, however, because of technical challenges, it was decided to focus on glass substrates for this portion of the work. SIMS analysis of recrystallized films on stainless steel showed that without a barrier layer, large quantities of transition metals diffused into the Si films during recrystallization. Although SixNy layers proved to be effective diffusion barriers, the nitride films tended to crack during recrystallization because of the large mismatch in the thermal expansion coefficient with the steel. Films on SnOx-coated glass proved problematic due to the rough nature of the substrate-film interface, which degraded depth resolution and obscured diffusion information in the depth profiles. As a result, most of the studies were performed on borosilicate glass (Corning 1737F). Solid-phase crystallized (SPC) films on glass showed no evidence of impurities from the glass, even up to annealing temperatures of 575°C for up to 24 h. In addition, therewasnochangeintheoxygencontent,which remained at 1018 at/cm3. This level is actually lower than the amount of oxygen present in CZ- grown Si (generally 1018 at/cm3). Experiments were performed to study the devolution of hydrogen from SPC a-Si:H films. Hydrogen is known to diffuse from a-Si during high- temperature anneals even without recrystallization, so it is important to know at what point in the nucleation and crystallization hydrogen is evolved from the material. Comparisons were made between films grown with high (14%) and low (4%) initial concentrations of hydrogen. The films with high hydrogen must be grown at lower substrate temperatures and therefore contain more oxygen. After annealing, the hydrogen levels were found to remain higher in the initially “high” level films. This may indicate higher defect densities, possibly also affected by the higher oxygen levels in these films. We also studied the diffusion of dopants from n- and p-type layers into i-layers. SIMS results show that B diffusion is lower than P for all temperatures studied, although 11 n-type P doped layers also had dopant concentrations of 1x1021 at/cm3 versus 2x1019 at/cm3 for the p-type doped layers. Phosphorus diffusion could be inhibited by annealing the n-type layer prior to deposition and crystallization of the i- layer. This work will continue in the coming year. Conduct experiments to quantify surface reactions that occur when using aqueous bath chemistries in the deposition of window layers on CIGS films: We have used our cluster tool for in-situ studies of the changes in surface chemistry and electronic structure that occur during chemical bath deposition of CdS. Results from this project can be roughly divided into three areas. (1) XPS and UPS determination of the chemical and electronic changes in the surfaces of CIGS thin films that are brought about by components (water and ammonia) of typical chemical bath deposition (CBD) of CdS window layers. We find that Group III elements are preferentially removed by aqueous ammonia, and that water alone is responsible for many but not all of the changes. Increasing duration air exposure of the ammonia treated surface results in the expected oxide formation, but also in the eventual increase in sodium. (2) XPS and ultraviolet photoelectron spectroscopy (UPS) determination of select electronic properties that are affected by exposure to aqueous reagents and how these changes are a function of the copper and gallium content of CIGS. We find that hot aqueous ammonia causes the n-type surface of as-grown CIGS to revert to p- type behavior as measured by quantitative determinations of the energetic position of the CIGS valence band maximum (VBM) relative to the Fermi energy. Band bending induced by the dopant cadmium was quantified and found to depend on the CIGS composition. The CIGS VBMs were found to be a function of copper content, as predicted theoretically, and to be n- type for very Cu-poor surfaces (Cu/(In+Ga) <0.3). These results are important in understanding the microscopic mechanism responsible for junction formation in the alloys that comprise CIGS. In the third part, (3) we have demonstrated an improved, surfactant-modified method of depositing CdS buffer layers with an aqueous chemical bath. We find that a non-ionic surfactant can be used as an additive in the chemical bath deposition of CdS buffer layers on CIGS and SnO2/glass substrates without changing the chemical or electronic properties of the CdS layers, and that for very thin buffer layers, addition of the surfactant leads to CIGS-based PV cells with significantly higher performance relative to standard CBD. The Photovoltaic R&D Fundamental ResearchPDF Image | DOE Solar Energy Technologies Program
PDF Search Title:
DOE Solar Energy Technologies ProgramOriginal File Name Searched:
38743.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |