Over the last decade attention has focused on two-dimensional materials such as graphene and molybendum diselenide (MoS2) as potential replacements for silicon in transistor channels because of superior performance characteristics. However, practical difficulties of integration with silicon remain and graphene behaves more like a metal as it has no electron energy band-gap.
Research into InSe layers only a few atoms thick, by a team from the universities of Manchester and Nottingham, has shown that unlike graphene, the material has a large energy gap allowing transistor action to be switched on and off and allowing for super-fast next-generation electronic devices.
"Ultra-thin InSe seems to offer the golden middle between silicon and graphene. Similar to graphene, InSe offers a naturally thin body, allowing scaling to the true nanometre dimensions. Similar to silicon, InSe is a very good semiconductor," said Sir Andre Geim, in a statement issued by the University of Manchester.
Thin InSe devices tend to be easily damaged by oxygen and water in the atmosphere and the research, published in Nature Nanotechnology details, how the researchers overcame this hurdle to the production of quality material. This was done by encapsulating it in hexagonal boron nitride under an argon atmosphere using technologies developed at the UK's National Graphene Institute. This allowed the creation of high-quality atomically-thin films of InSe for the first time.
The electron mobility at room temperature was measured at 2,000 cm 2/Vs, which compares with silicon at 1,400 cm 2/Vs.
The researchers believe that by following the methods now widely used to produce large-area graphene sheets, InSe could also soon be produced at a commercial level.
Related links and articles: