Interface Reactions in CdTe Solar Cell Processing

1997 ◽  
Vol 485 ◽  
Author(s):  
D. Albin ◽  
R. Dhere ◽  
A. Swartzlander-Guest ◽  
D. Rose ◽  
X. Li ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Thermal Treatments ◽  
Cdte Solar Cells ◽  
Interface Reactions ◽  
Chemical Vapor Deposited ◽  
Solar Conversion ◽  
Lift Off ◽  
Conversion Efficiencies ◽  
Substrate Temperatures ◽  
High Processing

AbstractCurrently, the best performing CdS/CdTe solar cells use a superstrate structure in which CdTe is deposited on a heated CdS/SnO2/Glass substrate. In the close-spaced-sublimation (CSS) process, substrate temperatures in the range 550°C to 620°C are common. Understanding how these high processing temperatures impact reactions at the CdS/CdTe interface in addition to reactions between previously deposited layers is critical. At the SnO2/CdS interface we have determined that SnO2 can be susceptible to reduction, particularly in H2 ambients. Room-temperature sputtered SnO2 shows the most susceptibility. In contrast, higher growth temperature chemical vapor deposited (CVD) SnO2 appears to be much more stable. Elimination of unstable SnO2 layers, and the substitution of thermal treatments for H2 anneals has produced total-area solar conversion efficiencies of 13.6% using non-optimized SnO2 substrates and chemical-bath deposited (CBD) CdS. Alloying and interdiffusion at the CdS/CdTe interface was studied using a new lift-off approach which allows enhanced compositional and structural analysis at the interface. Small-grained CdS, grown by a low-temperature CBD process, results in more CdTe1-x.Sx alloying (x=12–13%) relative to larger-grained CdS grown by high-temperature CSS (x7sim;2–3%). Interdiffusion of S and Te at the interface, measured with lift-off samples, appears to be inversely proportional to the amount of oxygen used during the CSS CdTe deposition. Our highest efficiency to date using CSS-grown CdS is 10.7% and was accomplished by eliminating oxygen during the CdTe deposition.

scholarly journals Investigation of Perovskite Solar Cells Employing Chemical Vapor Deposited Methylammonium Bismuth Iodide Layers

MRS Advances ◽  
2018 ◽  
Vol 3 (51) ◽  
pp. 3069-3074 ◽  
Author(s):  
Dominik Stümmler ◽  
Simon Sanders ◽  
Pascal Pfeiffer ◽  
Noah Wickel ◽  
Gintautas Simkus ◽  
...  
Keyword(s):  
Solar Cells ◽  
Environmental Concern ◽  
Perovskite Solar Cells ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Bismuth Iodide ◽  
Chemical Vapor Deposited ◽  
Free Environment ◽  
Conversion Efficiencies ◽  
Substrate Temperatures

ABSTRACTAlthough Pb-based perovskite solar cells already achieve power conversion efficiencies (PCE) beyond 20 %, the use of toxic Pb is causing considerable environmental concern. As a consequence, a variety of alternative cations have been investigated to replace Pb2+ in the perovskite structure. Methylammonium bismuth iodide (MA3Bi2I9, MBI) has shown promising results for environmentally benign and chemically stable devices. While the PCE of MBI-based solar cells are still comparably low, structural improvements have been made by using chemical vapor deposition (CVD). CVD allows for the well-controlled formation of coherent and dense MBI layers in contrast to solution-processing. In this work, CVD as a possible MBI fabrication method for efficient and size-scalable solar cells is discussed. The precursors MA iodide (MAI) and Bi iodide (BiI3) are deposited in an alternating deposition process forming the desired MBI perovskite on the heated substrate. Substrate temperatures as well as deposition times of each precursor are varied with the aim of forming coherent and dense MBI layers. Optimized films are further processed to solar cell prototypes and compared with solution-processed reference devices. The results reveal that CVD possesses great potential to enable the manufacture of MBI photovoltaic (PV) devices processed in a solvent-free environment.

Influence of Thermal Treatments on the Chemistry and Self-Assembly of Ge Nanoparticles on SiO2 Surfaces

2004 ◽  
Vol 830 ◽  
Author(s):  
Scott K. Stanley ◽  
Shawn S. Coffee ◽  
John G. Ekerdt
Keyword(s):  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Vapor ◽  
Thermal Treatments ◽  
X Ray ◽  
Agglomeration Process ◽  
Oxide Substrate ◽  
Temperature Programmed ◽  
Hot Filament ◽  
Substrate Temperatures

ABSTRACTGeH4 is thermally cracked over a hot filament depositing 0.7–15 ML Ge onto 2–7 nm SiO2/Si(100) at substrate temperatures of 300–970 K. Ge, GeHx, GeO, and GeO2 desorption is monitored through temperature programmed desorption in the temperature range 300–1000 K. Ge bonding changes are analyzed during annealing from 300–1000 K with X-ray photoelectron spectroscopy (XPS). Low temperature desorption features are attributed to GeO and GeH4. No GeO2 desorption is observed, but GeO2 decomposition to Ge through high temperature pathways is seen above 700 K. Germanium oxidization results from Ge etching of the oxide substrate, which is demonstrated through XPS. Ge nanoparticle formation on SiO2 is demonstrated using the agglomeration process. With these results, explanations for the difficulties of conventional chemical vapor deposition to produce Ge nanocrystals on SiO2 surfaces are proposed.

scholarly journals Chemical vapor deposited polymer layer for efficient passivation of planar perovskite solar cells

2020 ◽  
Vol 8 (38) ◽  
pp. 20122-20132
Author(s):  
Mahdi Malekshahi Byranvand ◽  
Farid Behboodi-Sadabad ◽  
Abed Alrhman Eliwi ◽  
Vanessa Trouillet ◽  
Alexander Welle ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Surface Passivation ◽  
Perovskite Solar Cells ◽  
Chemical Vapor ◽  
Polymer Layer ◽  
Chemical Vapor Deposited ◽  
Passivation Layers ◽  
Substrate Temperatures

Controlling the thickness and homogeneity of thin passivation layers on polycrystalline perovskite thin films is challenging. We report CVD polymerization of poly(p-xylylene) layers at controlled substrate temperatures for efficient surface passivation of perovskite films.

Stability of High Temperature Chemical Vapor Deposited Silicon Based Structures on Metals for Solar Conversion

2011 ◽  
Vol 11 (9) ◽  
pp. 8318-8322
Author(s):  
Isabelle Gelard ◽  
Guy Chichignoud ◽  
Elisabeth Blanquet ◽  
Hoan Nguyen Xuan ◽  
Ruben Cruz ◽  
...  
Keyword(s):  
High Temperature ◽  
Chemical Vapor ◽  
Chemical Vapor Deposited ◽  
Solar Conversion ◽  
Silicon Based

Ion Beam Induced Interfacial Reactions in Molybdenum Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 162-163
Author(s):  
L. J. Chen ◽  
L. S. Hung ◽  
J. W. Mayer
Keyword(s):  
Ion Beam ◽  
Chemical Vapor ◽  
Interfacial Reactions ◽  
Practical Applications ◽  
Microelectronic Devices ◽  
Recent Emergence ◽  
Chemical Vapor Deposited ◽  
Atomic Mixing ◽  
Silicon Interface ◽  
Kinetics Of

When an energetic ion penetrates through an interface between a thin film (of species A) and a substrate (of species B), ion induced atomic mixing may result in an intermixed region (which contains A and B) near the interface. Most ion beam mixing experiments have been directed toward metal-silicon systems, silicide phases are generally obtained, and they are the same as those formed by thermal treatment.Recent emergence of silicide compound as contact material in silicon microelectronic devices is mainly due to the superiority of the silicide-silicon interface in terms of uniformity and thermal stability. It is of great interest to understand the kinetics of the interfacial reactions to provide insights into the nature of ion beam-solid interactions as well as to explore its practical applications in device technology.About 500 Å thick molybdenum was chemical vapor deposited in hydrogen ambient on (001) n-type silicon wafer with substrate temperature maintained at 650-700°C. Samples were supplied by D. M. Brown of General Electric Research & Development Laboratory, Schenectady, NY.

Metal Microstructures in Advanced CMOS Devices

1996 ◽  
Vol 54 ◽  
pp. 358-359
Author(s):  
L. M. Gignac ◽  
K. P. Rodbell
Keyword(s):  
Grain Boundaries ◽  
Semiconductor Device ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Metal Films ◽  
Thin Metal ◽  
Electrical Performance ◽  
Thin Metal Films ◽  
Chemical Vapor Deposited ◽  
Boundary Properties

As advanced semiconductor device features shrink, grain boundaries and interfaces become increasingly more important to the properties of thin metal films. With film thicknesses decreasing to the range of 10 nm and the corresponding features also decreasing to sub-micrometer sizes, interface and grain boundary properties become dominant. In this regime the details of the surfaces and grain boundaries dictate the interactions between film layers and the subsequent electrical properties. Therefore it is necessary to accurately characterize these materials on the proper length scale in order to first understand and then to improve the device effectiveness. In this talk we will examine the importance of microstructural characterization of thin metal films used in semiconductor devices and show how microstructure can influence the electrical performance. Specifically, we will review Co and Ti silicides for silicon contact and gate conductor applications, Ti/TiN liner films used for adhesion and diffusion barriers in chemical vapor deposited (CVD) tungsten vertical wiring (vias) and Ti/AlCu/Ti-TiN films used as planar interconnect metal lines.

Light-Induced Degradation in Solar Cells with Hydrogenated Amorphous Silicon-Sulfur Active Layers

2002 ◽  
Vol 715 ◽  
Author(s):  
Wei Xu ◽  
P. C. Taylor
Keyword(s):  
Solar Cells ◽  
Practical Importance ◽  
Chemical Vapor ◽  
Photovoltaic Devices ◽  
Sulfur Concentration ◽  
Active Layers ◽  
Conversion Efficiencies ◽  
Hydrogenated Amorphous ◽  
Secondary Ion ◽  
Initial Conversion

AbstractWe have made a series of a-SiSx:H based solar cells, with a pin structure, in a multichamber plasma enhanced chemical vapor deposition (PECVD) system. The sulfur concentration ranges from zero to 5 x 1018 cm-3 as measured by secondary ion mass spectroscopy. The initial conversion efficiencies of cells in this series with sulfur concentrations ≤ 1018 cm-3 are approximately 7%. The time constants for degradation increase with increasing sulfur concentration, but not fast enough to be of practical importance in photovoltaic devices.

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