UCLA scientists and engineers have developed a new process for assembling semiconductor devices. The advance could lead to much more energy-efficient transistors for electronics and computer chips, diodes for solar cells and light-emitting diodes, and other semiconductor-based devices.
A research team led by UCLA scientists and engineers has developed a method to make new kinds of artificial “superlattices” — materials comprised of alternating layers of ultra-thin “two-dimensional” sheets, which are only one or a few atoms thick. Unlike current state-of-the art superlattices, in which alternating layers have similar atomic structures, and thus similar electronic properties, these alternating layers can have radically different structures, properties and functions, something not previously available.
Researchers in the US and Saudi Arabia are the first to have observed negative transconductance (NTC) inside multilayer molybdenum-disulphide (MoS2) transistors with optimized graphene/metal hybrid contacts. The NTC behaviour comes about thanks to competition between inter-layer charge transport and charge transport through a vertical potential barrier in the MoS2. This unique effect could be exploited for making frequency doublers and phase-shift keying circuits with only one multilayer transistor – something that would greatly simplify circuit design compared to conventional technology, says the team.
A new graphene nanostructure called graphene nanomesm (GNM) is able to open up a band gap in a large sheet of graphene to create a highly uniform, continuous semiconducting thin film that may be processed using standard planar semiconductor processing methods. [via newsroom.ucla]
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