Author: Elena A. GuliantsPublisher:
ISBN:
Category :
Languages : en
Pages : 366
Book Description
Polycrystalline Silicon Thin Films by Metal-induced Growth
Author: Elena A. GuliantsMetal-induced Growth of Microcrystalline Silicon Thin Films for Solar Cells
Author: Publisher:
ISBN:
Category : Polycrystals
Languages : en
Pages : 171
Book Description
The research focused on the process study for deposition of device quality polycrystalline silicon (poly-Si) thin films and solar cell fabrication by using a novel technique, metal-induced growth (MIG). Cobalt (Co) is introduced in the studies as a seed layer metal for the first time, while nickel (Ni) was another candidate. To grow the poly-Si, Co or Ni seed-layers were deposited on the foreign substrates by thermal evaporation with a few nm to 50 nm thickness. Substrates were transferred into the sputtering system for Si sputtering at elevated temperature from 525°C to 625°C. The Co or Ni reacted with sputtered Si to form metal disilicides which have very small lattice mismatch with Si (0.4% lattice mismatch for NiSi2 and Si, 1.2% lattice mismatch for CoSi2 and Si). The crystalline metal disilicides provide nucleation sites for poly-Si growth. With metal-induced growth, the relatively large-grain poly-Si films can be produced at relatively low temperatures on the various foreign substrates. Compared with Ni induced Si films, Co induced poly-Si has longer minority lifetime of 0.46 [mu]s as deposited and 1.3 [mu]s after annealing. A two-step sputtering method used for film deposition showed superiority over single step sputtering by achieving Si films with larger grain size (over 1 [mu]m) and less contamination. A double seed layer (5nm Co/50nm Ni) method was developed to produce the Si film with less Ni diffusion into Si. Metal-induced Si films were deposited on flexible thin tungsten substrates for solar cell fabrication. The good back Ohmic contact (metal disilicide) was formed naturally when the Si film was deposited. In this work, the solar cells were fabricated successfully by using metal-induced grown poly-Si. With the fabricated Schottky and P/N junction solar cells, the metal-induced growth processing parameters were studied. It was found that low-pressure sputtering, oxygen control during film growth, post-annealing and Si film hydrogenation are important to produce high quality poly-Si with fewer defects. The Schottky solar cell with optimized processing parameters showed the J[sub]sc and V[sub]oc of 12 mA/cm2 and 0.2 V, respectively. By passivating the MIG [mu]c-Si surface with hydrogenated nanocrystalline Si (nc-Si:H), the V[sub]oc was improved to 0.31 V. In addition, the current transport mechanism in Schottky and P/N junction devices were studied for different film growth conditions. The results showed that two-step sputtering, oxygen control and hydrogenation improved the quality of the Si film and devices.
Metal Silicide Nanowires for Nanoscale Contacts and Polycrystalline Silicon Thin Films for Solar Cells by Metal-induced Growth
Author: Handbook of Photovoltaic Silicon
Author: Deren YangPublisher: Springer
ISBN: 9783662564714
Category : Technology & Engineering
Languages : en
Pages : 0
Book Description
The utilization of sun light is one of the hottest topics in sustainable energy research. To efficiently convert sun power into a reliable energy – electricity – for consumption and storage, silicon and its derivatives have been widely studied and applied in solar cell systems. This handbook covers the photovoltaics of silicon materials and devices, providing a comprehensive summary of the state of the art of photovoltaic silicon sciences and technologies. This work is divided into various areas including but not limited to fundamental principles, design methodologies, wafering techniques/fabrications, characterizations, applications, current research trends and challenges. It offers the most updated and self-explanatory reference to all levels of students and acts as a quick reference to the experts from the fields of chemistry, material science, physics, chemical engineering, electrical engineering, solar energy, etc..
Metal Induced Growth of Si Thin Films and NiSi Nanowires
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 15
Book Description
Thin film silicon has many useful purposes. Among the applications are solar cells and thin film transistors. This project involves a new and potentially lower cost method to produce thin silicon films. The method is called metal induced growth (MIG). A thin catalyst metal layer deposited on a foreign low cost substrate serves as the basis for growth of a nanocrystalline silicon thin film with thickness of 5-10 microns and preferred orientation of (220). The silicon deposition by magnetron sputtering on the heated substrate resulted in columnar structured grains having a diameter up to about 0.5 microns. Schottky barrier solar cells fabricated on these films gave a photocurrent of about 5 mA/sq cm and open circuit voltage of 0.25 volts. A modified process gave NiSi crystalline nanowires with length up to 10 microns and diameter of about 50 nm.
Thin Film Transistors: Polycrystalline silicon thin film transistors
Author: Yue KuoPublisher: Springer Science & Business Media
ISBN: 9781402075063
Category : Thin film transistors
Languages : en
Pages : 528
Book Description
This is the first reference on amorphous silicon and polycrystalline silicon thin film transistors that gives a systematic global review of all major topics in the field. These volumes include sections on basic materials and substrates properties, fundamental device physics, critical fabrication processes (structures, a-Si: H, dielectric, metallization, catalytic CVD), and existing and new applications. The chapters are written by leading researchers who have extensive experience with reputed track records. Thin Film Transistors provides practical information on preparing individual functional a-Si: H TFTs and poly-Si TFTs as well as large-area TFT arrays. Also covered are basic theories on the a-Si: H TFT operations and unique material characteristics. Readers are also exposed to a wide range of existing and new applications in industries.
Metal-Induced Crystallization
Author: Zumin WangPublisher: CRC Press
ISBN: 9814463418
Category : Science
Languages : en
Pages : 317
Book Description
Crystalline semiconductors in the form of thin films are crucial materials for many modern, advanced technologies in fields such as microelectronics, optoelectronics, display technology, and photovoltaic technology. Crystalline semiconductors can be produced at surprisingly low temperatures (as low as 120C) by crystallization of amorphous semicon
Metal-Induced Crystallization
Author: Zumin WangPublisher: Pan Stanford
ISBN: 9789814463409
Category : Science
Languages : en
Pages : 0
Book Description
Crystalline semiconductors in the form of thin films are crucial materials for many modern, advanced technologies in fields such as microelectronics, optoelectronics, display technology, and photovoltaic technology. Crystalline semiconductors can be produced at surprisingly low temperatures (as low as 120 ̊C) by crystallization of amorphous semiconductors, which are put in contact with a metal. This so-called metal-induced crystallization process has attracted great scientific and technological interest because it allows the production of crystalline semiconductor-based advanced devices at very low temperatures, for example, directly on low-cost (but often heat-sensitive) substrates. This book provides the first comprehensive and in-depth overview of the current fundamental understanding of the metal-induced crystallization process and further elucidates how to employ this process in different technologies, for example, in thin-film solar cells and display technologies. It aims to give the reader a comprehensive perspective of the metal-induced crystallization process and thereby stimulate the development of novel crystalline semiconductor-based technologies.
Crystallization of Amorphous Silicon Thin Films Induced by Nanoparticle Seeds
Author: Taekon KimPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
ABSTRACT: Crystallization of amorphous Si (a-Si) thin film has received extensive interest for their attractive applications into Si thin film transistors and Si based solar cells. Among various crystallization techniques, Solid phase crystallization (SPC) and Excimer laser crystallization (ELC) were investigated. Firstly, Solid phase crystallization (SPC) of amorphous silicon thin films deposited by the DC magnetron sputtering system with a modification in nucleation step was investigated at low temperature. The thin film consists of polycrystalline nanoparticles embedded in an amorphous matrix which can act as nuclei during crystallization, resulting in a lower thermal energy for the nucleation. The lowering energy barrier for nucleation would shorten the transition time from amorphous into polycrystalline silicon resulting from the reduction of incubation time and also lower the processing temperature spontaneously. In addition, a comprehensive study of the growth mechanism of the sputtered amorphous silicon thin films is presented during annealing. Samples were prepared with various substrate temperatures and RF power in order to optimize the crystallization of a-Si after the deposition. Also, the effects of annealing condition were examined. Low pressure N2 ambient during SPC promoted crystallization of a-Si thin films and the crystallinity. The low pressure annealing had a large impact on the crystallinity and growth behavior of subsequent films.
Polycrystalline And Amorphous Thin Films And Devices
Author: Lawrence KazmerskiPublisher: Elsevier
ISBN: 0323156045
Category : Technology & Engineering
Languages : en
Pages : 321
Book Description
Polycrystalline and Amorphous Thin Films and Devices is a compilation of papers that discusses the electronic, optical, and physical properties of thin material layers and films. This compilation reviews the different applications of thin films of various materials used as protective and optical coatings, thermal transfer layers, and selective membranes from submicron- area VLSI memory units to large-area energy conservation devices. Some papers discuss the basic properties, such as growth, structure, electrical, and optical mechanisms that are encountered in amorphous and polycrystalline thin semiconductor films. For example, experiments on electronic structure of dislocations have led to a model for the intrinsic properties of grain boundaries in polycrystalline semiconductor thin films that can have an impact on the designs of high-efficiency, thin-film solar cells. Other papers review the problems encountered in these thin layers in active semiconductor devices and passive technologies. Techniques in film growth and control variables of source, substrate temperature, and substrate properties will determine the successful performance of the devices installed with these thin film layers. This compilation can prove valuable for chemists, materials engineers, industrial technologists, and researchers in thin-film technology.