Blue phosphorus mapped and measured for the first time
by Staff Writers
Berlin, Germany (SPX) Oct 18, 2018
The element phosphorus can exist in various allotropes and changes its properties with each new form. So far, red, violet, white and black phosphorus have been known. While some phosphorus compounds are essential for life, white phosphorus is poisonous and inflammable and black phosphorus - on the contrary - particularly robust.
Now, another allotrope has been identified: In 2014, a team from Michigan State University, USA, performed model calculations to predict that "blue phosphorus" should be also stable. In this form, the phosphorus atoms arrange in a honeycomb structure similar to graphene, however, not completely flat but regularly "buckled".
Model calculations showed that blue phosphorus is not a narrow gap semiconductor like black phosphorus in the bulk but possesses the properties of a semiconductor with a rather large band gap of 2 electron volts. This large gap, which is seven times larger than in bulk black phosphorus, is important for optoelectronic applications.
Blue P examined at BESSY II
They were able to measure by angle-resolved photoelectron spectroscopy the distribution of electrons in its valence band, setting the lower limit for the band gap of blue phosphorus.
Band structure influenced by the substrate
As a result, the top of the valence band that defines the one end of the semiconducting band gap agrees with the theoretical predictions about its energy position but is somewhat shifted.
Outlook: optoelectronic applications
"These also show a large semiconducting band gap but do not possess the honeycomb structure of blue phosphorus and, above all, cannot be grown directly on a substrate. Our work not only reveals all the material properties of this novel two-dimensional phosphorus allotrope but highlights the impact of the supporting substrate on the behavior of electrons in blue phosphorus, an essential parameter for any optoelectronic application."
Researchers quickly harvest 2-D materials, bringing them closer to commercialization
Boston MA (SPX) Oct 15, 2018
Since the 2003 discovery of the single-atom-thick carbon material known as graphene, there has been significant interest in other types of 2-D materials as well. These materials could be stacked together like Lego bricks to form a range of devices with different functions, including operating as semiconductors. In this way, they could be used to create ultra-thin, flexible, transparent and wearable electronic devices. However, separating a bulk crystal material into 2-D flakes for use in ele ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.