Novel forefront technological products such as, paper like displays, stretchable sensor skin, electronic textiles, and robotic sensors require high speed processing on unconventional form factor substrates, which can be bendable, flexible, stretchable and that they can assume different geometries. Therefore, field effect transistors with performances on a par with the wafer-based conventional electronics and at the same time flexible, compatible with sensitive substrates (plastic/rubber) are required. As the performance figures of FETs are intrinsically related to the ultimate electronic properties of the channel material and its interfaces, the need is to have materials responsive to all aforementioned demands.
At present, large area electronics on plastic and unusual format electronics use low performing materials such as organic conductors or metal oxide or alternatively newly emerging Si-like materials shaped into thin membranes, which are fabricated by multi step process exploiting the existing industry infrastructure with the related high costs. Graphene has been identified as a suitable electronic material for all kind of electronic technologies, owing to its mechanical, electrical, optical, chemical properties. Although graphene is the ideal material as a transparent electrode, it does not have a band gap hindering its use as a channel material. Here I propose studying a new range of 2D atomically thin materials, which share optical and mechanical properties of graphene, but in addition they are semiconducting with a band gap (1.1-1.9 eV).
Moreover, their high carrier mobility, uniquely distinguishes them from graphene as channel material for development of heterogeneous electronics. These materials are practically appealing as they offer realistic pathways to manufacture devices due to their 2 dimensional geometry facilitating integration, they do not have dangling bonds on the basal plane, allowing manipulation as individual particles in solution and they have unique mechanical features, with effects related to shape distortions and folding. Simultaneously, they present quantum and other size-dependent effects leading to a wealth of electronic, phonon dynamics and optical properties, not found in zero- and one-dimensional materials, offering opportunities to extend the frontiers of their applications to spintronics, photovoltaic, catalysis etc. The main objective is to demonstrate low-voltage n/p-type FETs operating in logic inverters, which are the elemental units of logic electronics.
Toward this end, the aim is to develop novel solution phase processing necessary to isolate monolayer flakes with preserved atomic and electronic structure, from their 3D counterpart and create stable inks of these platelets. These inks will be then exploited to establish a reliable array of scalable deterministic assembly techniques of the flakes onto any substrates in the form of highly uniform ultrathin films over large areas. These materials will be interfaced with the atomically thin organic dielectrics, which secure low-power operation. In addition both, 2D membranes as well as the organic components are transparent in the optical range due to their ultimately thin thickness leading to semitransparent devices.
The solution based processing at room temperature will ensure low cost manufacturing and compatibility with any plastic/rubber substrates, and reduction of energy employed for fabrication addressing also worldwide need for energy saving. The raw materials cost is also competitive in comparison with the existing materials for electronics. Overall the proposed research can lead to new economic benefits, extend the frontiers of the present electronic technology, and open new scenarios in fundamental science in respect to new quantum and other size-phenomena.
|