Interface phases and the future of the nanotransistor

Advances in the epitaxial growth of ultra-thin films and heterojunctions have made viable new classes of device applications that may sustain the semiconductor roadmap for another decade. However, this progress will require an in-depth understanding and utilization of electronic processes at the nanoscale. One of the central issues is the role of interfaces between materials, where most of the electronic properties of the system are determined. In this talk, I will discuss recent fundamental advances in our understanding of the physics of nano-scale interfaces and introduce the concept of interface “phase”, a region of structure-specific chemical bonding that determines the properties of heterojunctions. This interface phase results in a “Coulomb buffer” that can be tuned to adjust the overall electronic properties of the system. These ideas will be elucidated through the prototypical example of the Field Effect Transistor, where the interfaces between semiconductors, oxides and metals will be analyzed in terms of the novel concepts of interface phase and Coulomb buffer. ( Work done in collaboration with M. Nunez (NCSU), R.A. McKee (ORNL) and W.J. Walker (ORNL))