Combinatorial Studies for High Density Si and Ge Nanoparticle Arrays

2006 ◽  
Vol 933 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt

ABSTRACTA simple combinatorial approach for studying chemical and physical vapor deposition (CVD and PVD) nanoparticle growth is presented utilizing temperature and precursor flux gradients across sample surfaces. Large temperature gradients (450-700 °C) are induced covering the entire range of interest for most CVD and PVD processes. Precursor flux gradients may also be introduced simultaneously or separately using a tungsten cracking filament mounted on a translation arm. Theory and calibration experiments are explained and results from a study on Ge nanoparticle growth on HfO2 surfaces are presented and analyzed. This method drastically decreases experimental time required to investigate nanoparticle growth and identify optimum deposition conditions. Furthermore, this approach greatly facilitates preparation of library samples containing a wide range (several orders of magnitude) in variation of nanoparticle sizes, density, and composition for subsequent studies.

2019 ◽  
Vol 293 ◽  
pp. 83-95
Author(s):  
Marek Szindler

The use of thin films in optoelectronic and photovoltaic devices is aimed at improving the physical properties of the substrate material. The modification of the surface of the silicon substrate is thus one of the greatest challenges in research on photovoltaic materials, in order to achieve even greater efficiency or better adapt their properties depending on the application. The technologies of applying layers vary depending on the effect to be obtained and the material from which the layer is formed. In practice, the most common method is chemical vapor deposition and physical vapor deposition, and the most commonly applied optical materials are SiO2, TiO2 and Si3N4.This paper presents the results of investigations on morphology and optical properties of the prepared aluminium oxide thin films. Thin films were prepared with use of sol-gel spin coating method. Surface morphology studies were carried out using an atomic force microscope. To characterize the surface of the thin films, 3D images and histograms of the frequency of individual inequalities were made. In order to characterize the optical properties of Al2O3 thin films, the reflectance and light transmission tests were performed using a spectrophotometer. Optical constants were determined using a spectroscopic ellipsometer. Results and their analysis show that the sol-gel method allows the deposition of homogenous thin films of Al2O3 with the desired geometric characteristics and good optical properties. Uniform, continuous thin layers with a roughness not exceeding a few nanometres were deposited. Their deposition enabled to reduce the reflection of light from the polished substrate below 15% in a wide range (425-800nm) while maintaining high transparencies (over 90%). The obtained results causes that mentioned thin films are good potential material for optics, optoelectronics and photovoltaics.


2014 ◽  
Vol 597 ◽  
pp. 153-156
Author(s):  
Ching Yen Ho ◽  
Wen Chieh Wu

This paper investigates ionic distribution generated by electron beam (EB) during Physical Vapor Deposition (PVD). EB-PVD has a wide range of applications in thermal barrier coatings (TBCs) due to favorable characteristics compared with other coating processes. EB-PVD is an important material coating method that utilizes electron beams as heat sources to evaporate materials, which are then deposited on a substrate. Therefore EB-induced ionic distribution dominates the quality and thickness of the final coating on the substrate. Assuming the EB-generated plasma to be only a function of radial direction, the steady-state equations of continuity and motion combined with Posson’s equation were utilized to analyze the plasma distributions along the radial direction. The available experimental data are also used to validate the model. The results show that the coating efficiency can be improved by decreasing the ratio of the electron thermal energy to the initial ion energy and increasing the ratio of the initial ion density to the initial electron density. The uniformity of coating can be achieved by reducing the initial ion density.


2015 ◽  
Vol 169 ◽  
pp. 195-201 ◽  
Author(s):  
Pedro Salazar ◽  
Victor Rico ◽  
Rafael Rodríguez-Amaro ◽  
Juan P. Espinós ◽  
Agustín R. González-Elipe

Author(s):  
Stephen Stagon ◽  
Ryan Scherzer

This entry reports on the facile fabrication and characterization of aluminum (Al) nanoparticle arrays that absorb strongly in deep ultraviolet. First, Al nanoparticle arrays are fabricated using glancing angle physical vapor deposition and have average diameters of ~30 nm. After subsequent annealing, the structures become oxidized on the exterior with an Al metal core. Ultraviolet visible spectroscopy is performed to characterize the optical absorbance of the structures before and after annealing. The as-fabricated structures show strong and broad absorption centered near ~230 nm, and annealing in air at 400°C results in tightening and blue shifting of the absorption peak. Additionally, annealing results in a decrease in overall absorption intensity. These new results may be potentially useful for tandem or plasmon-assisted photovoltaics.


2008 ◽  
Author(s):  
Rong Wang ◽  
Ronghui Ma

In this study, a comprehensive transport model is developed for Halide Chemical Vapor Deposition (HCVD) system which includes gas dynamics, heat and mass transfer, gas-phase and surface chemistry, and radio-frequency induction heating. This model addresses transport of multiple chemical species in high temperature environment with large temperature difference and complex chemical reactions in gas-phase and on the deposition surface. Numerical modeling of the deposition process in a horizontal hot-wall reactor using SiCl4/C3H8/H2 as precursors has been performed over a wide range of operational parameters to quantify the effects of processing parameters on the film growth. The simulations of the deposition process provide detailed information on the gas-phase composition as well as the distributions of gas velocity and temperature in the reactor. The deposition rate on the substrate surface is also predicted. The results illustrate that deposition temperature and the flow rate of carrier gas play an important role in determining the processing conditions and deposition rate. A high concentration of HCl exists in the growth chamber and the etching of the SiC films by HCl has significant effect on the deposition rate. The modeling approach can be further used to improve reactor design and optimization of processing conditions.


2011 ◽  
Vol 55-57 ◽  
pp. 183-187 ◽  
Author(s):  
Zhao Hui Hu ◽  
Yi Li ◽  
Li Ma ◽  
Hong Jun Liu

Ti-TiAl multi-layered materials have been prepared by electron beam physical vapor deposition technique. The tensile behavior of samples at room temperature and high temperature was tested, and then the deformation mechanism at different temperature was analyzed according to the fracture surface. The results show that the tensile curves hot-pressed samples have a broad step during the plastic deformation process, and the breaking strain of the sample has been increased for a wide-range. The presence of Ti layers have led to the cracks stagger along the inter-laminar interface or the layer due to which micro laminate expresses a good characteristic of delayed fracture. With the increase of temperature, the bulk modulus and yield strength of multi-layered Ti-TiAl have been increased abnormally due to the anomalous yield strengthening behavior of TiAl intermetallic.


Author(s):  
B. Li ◽  
P. A. Clark ◽  
K. H. Church

The development of functional and reliable miniaturized devices including Micro Electro Mechanical Systems (MEMS) has stressed the manufacturing and packaging processes. The traditional micro fabrication techniques, such as lithography, physical vapor deposition (PVD), chemical vapor deposition (CVD) and etching, are layer-by-layer processes and mostly suitable for thin-filmed devices. LIGA (an acronym from German words for lithography, electroplating, and molding) is a newly developed process for thick metallic devices; however, it involves electroplating process and high quality molds, which are hard to move after electroforming. In all the processes mentioned above, masks and photoresist processing are inevitable, which complicates the whole process and increases the processing time and the total cost. It is also well known that packaging is another barrier for the advancement of MEMS. MEMS packaging, which is required to provide mechanical support, environmental protection and electrical connection to other system components, is much more complicated as compared to electronic components due to the moving structures, fluids or chemicals involved. It is the most expensive process in micromachining. Therefore, enabling tools and technologies are greatly needed for the fabrication and packaging of complicated devices and highly integrated micro assemblies. In this paper, we will present novel direct-print dispensing techniques and robust tools for 21st century manufacturing and packaging. Comparing to other dispensing technologies such as time-pressure needle dispensing, screen printing, pin transfer and jetting, nScrypt’s pumping techniques can dispense materials with precise volume control for 10’s of Pico liter resolution, accurate placement or alignment within a few microns, conformably print on exaggerated surfaces of 10’s of centimeters, and are extremely flexible with materials and patterns. The dispensing tip (nozzle) is optimized to reduce the pressure drop as compared to the traditional tubing needles. Comparing to traditional micro fabrication technologies, our direct-print dispensing technology is maskless and thus a cost effective process. While micro-dispensing is a solution based approach, it has the advantage of not being a wet process such as wet etching or electroplating. Direct-print dispensing of micro lines, micro dots, and three-dimensional structures will be presented. The technology has a wide range of applications in the manufacturing and packaging of micro/meso-scale devices and bio structures.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2926
Author(s):  
Daniel Alves Barcelos ◽  
Diana C. Leitao ◽  
Laura C. J. Pereira ◽  
M. Clara Gonçalves

Inorganic glass is a transparent functional material and one of the few materials that keeps leading innovation. In the last decades, inorganic glass was integrated into opto-electronic devices such as optical fibers, semiconductors, solar cells, transparent photovoltaic devices, or photonic crystals and in smart materials applications such as environmental, pharmaceutical, and medical sensors, reinforcing its influence as an essential material and providing potential growth opportunities for the market. Moreover, inorganic glass is the only material that is 100% recyclable and can incorporate other industrial offscourings and/or residues to be used as raw materials. Over time, inorganic glass experienced an extensive range of fabrication techniques, from traditional melting-quenching (with an immense diversity of protocols) to chemical vapor deposition (CVD), physical vapor deposition (PVD), and wet chemistry routes as sol-gel and solvothermal processes. Additive manufacturing (AM) was recently added to the list. Bulks (3D), thin/thick films (2D), flexible glass (2D), powders (2D), fibers (1D), and nanoparticles (NPs) (0D) are examples of possible inorganic glass architectures able to integrate smart materials and opto-electronic devices, leading to added-value products in a wide range of markets. In this review, selected examples of inorganic glasses in areas such as: (i) magnetic glass materials, (ii) solar cells and transparent photovoltaic devices, (iii) photonic crystal, and (iv) smart materials are presented and discussed.


2021 ◽  
Vol 9 ◽  
Author(s):  
Berik Uzakbaiuly ◽  
Aliya Mukanova ◽  
Yongguang Zhang ◽  
Zhumabay Bakenov

With the development of smart electronics, a wide range of techniques have been considered for efficient co-integration of micro devices and micro energy sources. Physical vapor deposition (PVD) by means of thermal evaporation, magnetron sputtering, ion-beam deposition, pulsed laser deposition, etc., is among the most promising techniques for such purposes. Layer-by-layer deposition of all solid-state thin-film batteries via PVD has led to many publications in the last two decades. In these batteries, active materials are homogeneous and usually binder free, which makes them more promising in terms of energy density than those prepared by the traditional powder slurry technique. This review provides a summary of the preparation of cathode materials by PVD for all solid-state thin-film batteries. Cathodes based on intercalation and conversion reaction, as well as properties of thin-film electrode–electrolyte interface, are discussed.


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