Drawing on the Nanometer-placement Capabilities of Self-assembly Fabrication Methods, the Authors Propose a New Nanoscale Device Based on a Single-molecule Optical Phenomenon Called Resonance Energy

......Nanoscale devices offer the possibility of a new era in computing. Device sizes at the molecular scale will let computer architects deploy a plethora of devices— creating, for example, million-core designs. Furthermore, because nanoscale devices could contain a significant amount of computational circuitry in an area smaller than a typical biological cell, they could prompt the emergence of new application domains. To date, there is no clear winner in the field of nanotechnology for computing. CMOS continues its relentless march toward smaller feature sizes, but the cost of fabrication facilities increases with each new technology generation. Carbon nanotube and ring-gated nanorod field-effect transistors (FETs) are hopeful candidates, but obtaining control over the precise device length and achieving precise placement for arbitrary patterns remain open challenges. This article proposes a new nanoscale technology for computing based on singlemolecule optical devices called chromophores. In isolation, a given chromophore absorbs photons of a specific wavelength and emits photons at a different, lowerenergy, wavelength. However, when appropriate chromophores are placed a few nanometers apart, the energy of an absorbed photon can be transferred to a neighboring chromophore through a process called resonance energy transfer (RET). This process provides the theoretical foundation for the creation of pass gates (both inverting and noninverting), using four chromophores per gate. These gates form a complete Boolean logic set, which we call RET logic. A key requirement for RET logic is to place unique chromophores within a few nanometers of each other. Unfortunately, creating such devices using conventional top-down fabrication techniques is costly Constantin Pistol Chris Dwyer Alvin R. Lebeck