Layered semiconducting black arsenic phosphorus as an
alternative to silicon
(July 9, 2015) Graphene,
the only one atom thick carbon network, achieved overnight fame with the 2010
Nobel Prize. But now comes competition: Such layers can also be formed by black
phosphorous. Chemists at the Technische Universität München (TUM) have now
developed a semiconducting material in which individual phosphorus atoms are
replaced by arsenic. In a collaborative international effort, American
colleagues have built the first field-effect transistors from the new material.
For many decades silicon has formed the basis of modern
electronics. To date silicon technology could provide ever tinier transistors
for smaller and smaller devices. But the size of silicon transistors is
reaching its physical limit. Also, consumers would like to have flexible
devices, devices that can be incorporated into clothing and the likes. However,
silicon is hard and brittle. All this has triggered a race for new materials
that might one day replace silicon.
Black arsenic phosphorus might be such a material. Like
graphene, which consists of a single layer of carbon atoms, it forms extremely
thin layers. The array of possible applications ranges from transistors and
sensors to mechanically flexible semiconductor devices. Unlike graphene, whose
electronic properties are similar to those of metals, black arsenic phosphorus
behaves like a semiconductor.
Phosphorene vs.
graphene
A cooperation between the Technical University of Munich and
the University of Regensburg on the German side and the University of Southern
California (USC) and Yale University in the United States has now, for the
first time, produced a field effect transistor made of black arsenic
phosphorus. The compounds were synthesized by Marianne Koepf at the laboratory
of the research group for Synthesis and Characterization of Innovative
Materials at the TUM. The field effect transistors were built and characterized
by a group headed by Professor Zhou and Dr. Liu at the Department of Electrical
Engineering at USC.