ANALYTICAL CHALLENGES in MOLECULAR ELECTRONICS

摘要

In the late 1990s, molecular electronics emerged rapidly and spectacularly as an area of research that encompasses several paradigms in which electrons are transported through molecules (1, 2). An often-stated motivation for pursuing these devices is to extend Moore's law of the exponential growth in microelectronic device density. The state of the art in silicon technology is a minimum feature size of 65 nm. If the trend toward miniaturization continues, eventually devices will have to be fabricated on the molecular scale of a few nanometers. This article will address the promise of molecular electronic devices and some of the problems with characterizing electronic components with molecular dimensions. An early and widely publicized molecular electronic component was a bistable rotaxane molecule with 2 configurations that, in principle, could act as a single-molecule, 1-bit memory cell (3, 4). The molecule was switched between two metastable configurations by an applied electrical pulse. If such a device could be mass-produced in microelectronic circuits, it would represent an increase in device density of 2-3 orders of magnitude. In addition to the fabrication challenges associated with the further extension of Moore's law, the physical properties of silicon become a limitation as feature size decreases. For example, insufficient tunneling barriers and capacitance associated with very thin silicon oxide films (<10 nm) can significantly degrade device performance.