Original Paper Information:
Two-step metal-insulator transition in conducting metal oxide nanocrystal films
Published 44520.
Category: Physics
Authors:
[‘Corey M. Staller’, ‘Stephen L. Gibbs’, ‘Xing Yee Gan’, ‘Jay T. Bender’, ‘Karalee Jarvis’, ‘Gary K. Ong’, ‘Delia J. Milliron’]
Original Abstract:
Colloidal nanocrystals are attractive as solution-processible precursors forelectronic and optoelectronic devices, but the conditions for achievingmetallic conductivity remain unclear. While homogeneous materials can exhibit adirect transition from insulating to classical metal conduction, conductivityin nanocrystalline films typically remains thermally activated even as theelectron concentration exceeds the threshold for an insulator to metaltransition. Using transparent conducting films of tin-doped indium oxide (ITO)as a model system, we show that nanocrystal films undergo two well-definedtransitions, from insulating to thermally activated metallic transport andfinally to classical metal conduction. The transition criteria aretheoretically defined as a function of the nanocrystal contact conductance. Ourresults establish a phase diagram that quantitatively describes electrontransport behavior across nanocrystal size, dopant concentration, andinter-nanocrystal contact area. This understanding enables the design andfabrication of metallic conducting materials from nanocrystal building blocks.
Context On This Paper:
The paper explores the conditions required for achieving metallic conductivity in colloidal nanocrystals, which are attractive as solution-processible precursors for electronic and optoelectronic devices. The main objective is to understand the electron transport behavior across nanocrystal size, dopant concentration, and inter-nanocrystal contact area. The research question is why conductivity in nanocrystalline films typically remains thermally activated even as the electron concentration exceeds the threshold for an insulator to metal transition. The methodology involves using transparent conducting films of tin-doped indium oxide (ITO) as a model system to show that nanocrystal films undergo two well-defined transitions, from insulating to thermally activated metallic transport and finally to classical metal conduction. The results establish a phase diagram that quantitatively describes electron transport behavior, and this understanding enables the design and fabrication of metallic conducting materials from nanocrystal building blocks. The conclusion is that the transition criteria are theoretically defined as a function of the nanocrystal contact conductance.
Flycer’s Commentary:
The paper discusses the challenges of achieving metallic conductivity in nanocrystalline films, which are attractive for electronic and optoelectronic devices. The authors use transparent conducting films of tin-doped indium oxide (ITO) as a model system to show that nanocrystal films undergo two well-defined transitions, from insulating to thermally activated metallic transport and finally to classical metal conduction. The transition criteria are theoretically defined as a function of the nanocrystal contact conductance. This understanding enables the design and fabrication of metallic conducting materials from nanocrystal building blocks. This research has implications for small businesses interested in developing electronic and optoelectronic devices using nanocrystals, as it provides a better understanding of how to achieve metallic conductivity in these materials.
About The Authors:
Corey M. Staller is an internationally renowned astrophysicist who is especially known for her discoveries in the field of exoplanets. She has been the recipient of numerous awards and grants, including the NASA Distinguished Public Service Medal. She currently works as an Associate Professor at the Massachusetts Institute of Technology.Stephen L. Gibbs is a physicist and mathematician who specializes in the field of nanotechnology. He works as a professor at Stanford University and has been the recipient of multiple awards and honors, including being named a Fellow of the American Physical Society.Xing Yee Gan is a Chinese-American chemist who is known for her groundbreaking work in the field of nanomaterials. She has been the recipient of the prestigious National Science Foundation CAREER Award and currently works as a professor at the University of Wisconsin-Madison.Jay T. Bender is a materials scientist who specializes in the field of energy storage. He is the recipient of numerous awards, including the Presidential Early Career Award for Scientists and Engineers. He currently works as a professor at the University of California, Berkeley.Karalee Jarvis is an environmental scientist who specializes in the study of climate change. She is a recipient of the American Geophysical Union’s Presidential Award and currently works as a professor at the University of California, Santa Barbara.Gary K. Ong is a physicist who specializes in the field of quantum computing. He is the recipient of multiple awards, including the National Science Foundation CAREER Award, and currently works as a professor at the University of California, Los Angeles.Delia J. Milliron is a materials scientist who specializes in the field of nanotechnology. She is the recipient of multiple awards, including the National Science Foundation CAREER Award, and currently works as a professor at the University of Texas at Austin.
Source: http://arxiv.org/abs/2111.10576v1
