Princeton Docket # 13-2914
Research in the department of chemistry and department of physics, Princeton University, has led to improved methods for controlling and altering band gaps in commercially useful materials such as amorphous silicon, germanium and diamond. These methods can be used in the design of isotropic semiconducting materials which are used in a wide range of electronic applications such as photovoltaic cells, x-ray sensors, light sensors (scanners, multilayer color detectors), position sensitive detectors and thin-film transistors (LCD screens). These new materials will have distinctive electronic, phononic, and elastic properties.
The new materials retain the isotropy of an amorphous solid but have nearly the same long-range correlations in density fluctuations (hyperuniformity) of a crystal. The result is a globally uniform atomic or molecular material with distinctive electronic and phononic transport properties.
To date computer simulations have been used to determine how to synthesize isotropic semiconductors that are nearly hyperuniform and to show that their electronic band
gaps are wider and more uniform than those of ordinary amorphous semiconductors, making them advantageous for electronic and photovoltaic applications of semiconductors.
Xie R, Long GG, Weigand SJ, Moss SC, Carvalho,T, Roorda S, Hejna M, Torquato S, Steinhardt PJ, (2013) Hyperuniformity in amorphous silicon base on the measurement of the infinite-wavelngth limit of the structure factor. PNAS vol 110 no. 33: 13250-13254.
M. Hejna, P. J. Steinhardt, and S. Torquato, Nearly Hyperuniform Network Models of Amorphous Silicon, Physical Review B, 87, 245204 (2013).
Professor Paul Steinhardt
Paul J. Steinhardt is the Albert Einstein Professor in Science and director of the Princeton Center for Theoretical Science at Princeton University, where he is jointly appointed to the physics and astrophysical sciences departments. Steinhardt's research spans problems in particle physics, astrophysics, cosmology and condensed matter physics. In collaboration with Dov Levine of the Technion-Israel Institute of Technology, Steinhardt introduced the concept of quasicrystals -- a new phase of solid matter with disallowed crystallographic symmetries -- and Steinhardt has continued to make contributions to understanding their unique mathematical and physical properties.
Steinhardt received his B.S. in physics from the California Institute of Technology and holds master’s degree and Ph.D. in physics from Harvard University. Steinhardt is a fellow of the American Physical Society and a member of the National Academy of Sciences. He shared the P.A.M. Dirac Medal from the International Centre for Theoretical Physics in 2002 for the development of the inflationary model of the universe, and the Oliver E. Buckley Prize of the American Physical Society in 2010 for his contributions to the theory of quasicrystals.
Professor Salvatore Torquato
Salvatore Torquato is a professor in the Princeton University Department of Chemistry and the Princeton Institute for the Science and Technology of Materials, and a senior faculty fellow at the Princeton Center for Theoretical Science. A researcher who is broadly interested in understanding the behavior of materials at the microscopic level, Torquato employs the techniques of statistical mechanics to study packing problems, colloids, liquids, glasses, quasicrystals and crystals, hyperuniform materials, disordered heterogeneous materials, materials optimization, and self-assembly theory.
Torquato holds a bachelor’s degree from Syracuse University and a master’s degree and Ph.D. from the State University of New York at Stony Brook, all in mechanical engineering. He is a fellow of the Society for Industrial and Applied Mathematics (SIAM) and the American Physical Society. His many research awards include the Society for Industrial and Applied Mathematics's Ralph E. Kleinman Prize, the David Adler Lectureship Award in Material Physics, American Physical Society, 2009, and the Society of Engineering Science's William Prager Medal.
Miroslav Hejna received his bachelor's and master's degree in Mathematics
from the University of Cambridge in 2006 and 2007 respectively and received
a Ph.D. in Theoretical Physics from Princeton University in 2013. His research
interests include hyperuniform disordered solids, structure of amorphous
tetrahedral network materials and understanding the relation between the degree
of hyperuniformity of a disordered solid and its electronic properties. He is
currently employed as a postdoctoral research associate in the Department
of Physics at the University of Illinois, Urbana-Champaign.