amorphous silicon

amorphous silicon
Name	Amorphous Silicon

amorphous silicon is a type of non-crystalline solid that exhibits unique electrical properties similar to those of crystalline silicon, but with a more disordered atomic structure, similar to glass. This property makes it useful for various electronic devices, including solar cells developed by Sharp Corporation, Toshiba, and Panasonic. The study of amorphous silicon is closely related to the work of Nobel Prize winners like Willis Lamb, Polykarp Kusch, and John Bardeen, who contributed to the understanding of semiconductor physics at Bell Labs and University of Illinois at Urbana-Champaign. Amorphous silicon has been explored in various research institutions, including Stanford University, Massachusetts Institute of Technology, and California Institute of Technology.

Introduction

Amorphous silicon is a metastable form of silicon that can be deposited at low temperatures, making it suitable for use on flexible substrates like plastic or metal foil, which are often used in flexible electronics developed by companies like Samsung Electronics and LG Electronics. The lack of long-range order in amorphous silicon gives it a higher density of states than crystalline silicon, which affects its optical properties and makes it useful for applications like thin-film transistors used in liquid crystal displays manufactured by AU Optronics and Chunghwa Picture Tubes. Researchers at IBM, Intel, and Texas Instruments have studied the properties of amorphous silicon to improve its performance in various devices. The unique properties of amorphous silicon have also been explored in collaboration with European Organization for Nuclear Research and National Institute of Standards and Technology.

Properties

The properties of amorphous silicon are influenced by its disordered structure, which is characterized by a high degree of bond angle disorder and bond length disorder, similar to amorphous carbon and amorphous metals studied at Los Alamos National Laboratory and Oak Ridge National Laboratory. This disorder leads to a higher electrical resistivity than crystalline silicon, making it useful for applications like photovoltaic cells developed by SunPower, First Solar, and Trina Solar. The optical bandgap of amorphous silicon is also wider than that of crystalline silicon, which makes it more suitable for use in tandem solar cells designed by University of California, Berkeley and Georgia Institute of Technology. Scientists at Harvard University, University of Oxford, and University of Cambridge have investigated the properties of amorphous silicon to understand its behavior in different environments. The properties of amorphous silicon have also been compared to those of germanium and tin at Argonne National Laboratory and Brookhaven National Laboratory.

Production

Amorphous silicon can be produced using various techniques, including plasma-enhanced chemical vapor deposition developed by General Electric and Westinghouse Electric Corporation, sputtering used by Applied Materials and KLA-Tencor, and evaporation employed by Varian Semiconductor Equipment Associates and Veeco Instruments. The choice of production method depends on the desired properties of the amorphous silicon film, such as its thickness, uniformity, and doping level, which are critical in semiconductor manufacturing at Taiwan Semiconductor Manufacturing Company and Samsung Electronics. Researchers at University of Tokyo, University of Michigan, and Carnegie Mellon University have developed new methods for producing amorphous silicon with improved properties. The production of amorphous silicon has also been optimized in collaboration with National Renewable Energy Laboratory and Sandia National Laboratories.

Applications

Amorphous silicon has a wide range of applications, including solar cells developed by Suntech Power, Yingli Solar, and Trina Solar, thin-film transistors used in liquid crystal displays manufactured by AU Optronics and Chunghwa Picture Tubes, and image sensors designed by Canon Inc. and Nikon Corporation. It is also used in flexible electronics, such as flexible displays developed by Samsung Electronics and LG Electronics, and wearable devices designed by Apple Inc. and Google. The use of amorphous silicon in medical devices has also been explored, including implantable devices developed by Medtronic and Boston Scientific. Scientists at Stanford University, Massachusetts Institute of Technology, and California Institute of Technology have developed new applications for amorphous silicon. The applications of amorphous silicon have also been expanded in collaboration with European Space Agency and National Aeronautics and Space Administration.

History

The history of amorphous silicon dates back to the 1960s, when it was first produced by Stanford University researchers using plasma-enhanced chemical vapor deposition developed by General Electric and Westinghouse Electric Corporation. The first amorphous silicon solar cells were developed in the 1970s by University of Delaware and Institute of Energy Conversion, and they had an efficiency of around 1%. Since then, the efficiency of amorphous silicon solar cells has increased significantly, with modern cells achieving efficiencies of over 10% developed by Sharp Corporation, Toshiba, and Panasonic. The development of amorphous silicon has involved the work of many researchers, including Nobel Prize winners like Willis Lamb, Polykarp Kusch, and John Bardeen, who contributed to the understanding of semiconductor physics at Bell Labs and University of Illinois at Urbana-Champaign. Historians at Harvard University, University of Oxford, and University of Cambridge have studied the history of amorphous silicon to understand its development.

Research_and_development

Research and development of amorphous silicon is ongoing, with scientists at IBM, Intel, and Texas Instruments working to improve its properties and applications. New techniques, such as nanoparticle deposition developed by University of California, Los Angeles and University of Texas at Austin, are being developed to produce amorphous silicon with improved properties. The use of amorphous silicon in quantum computing and artificial intelligence is also being explored, with researchers at Google, Microsoft, and Amazon working on new applications. Collaborations between National Institute of Standards and Technology, National Renewable Energy Laboratory, and Sandia National Laboratories have accelerated the development of amorphous silicon. The research and development of amorphous silicon have also involved international collaborations with European Organization for Nuclear Research and National Research Council of Canada.

Category:Materials science