| AVS 55th International Symposium & Exhibition | |
| Biomaterial Interfaces | Wednesday Sessions |
| Session BI+NC-WeM |
| Session: | Quantitative Nanoscale Sensing and Single Molecule Techniques |
| Presenter: | S. Vasudevan, University of Virginia |
| Authors: | S. Vasudevan, University of Virginia K. Walczak, University of Virginia A.W. Ghosh, University of Virginia |
| Correspondent: | Click to Email |
The future of nanoelectronics will depend not only on the capability to engineer ‘smart’ materials, but also on the ability to exploit new quantum phenomena that emerge at submicroscopic length scales. Molecular electronics has often been advocated as an ideal successor to silicon-based, complementary metal oxide semiconductor technology (CMOS). But its development has been thwarted by problems like poor gatability and low mobilities. Therefore we need to explore hybrid devices that do not compete with CMOS, but instead add novel functionalities by exploiting properties that are unique to molecules, such as their tendency to function as strongly correlated systems. Thus we need to account for more complex effects than usual semiclassical theory provides. In this paper we develop a theory for a new class of electronic devices that exploit correlated quantum scattering in a transistor channel. In these devices, molecules attach to the surface of a transistor channel; the chemical bonding leads to the transfer of charge and spectral weight between the molecule and the silicon surface. The overlap of molecular and silicon wavefunctions serves to passivate existing surface states as well as to create new localized molecular trap levels inside the silicon band-gap. At resonance driven by a gate, the traps are stochastically filled and emptied by the channel electrons, blocking and unblocking the channel. The resulting two-state random telegraph signal (RTS) can be used to locate the trap position both spectrally as well as spatially. This allows us to characterize and detect molecular species through unique nano-‘barcodes’. The effect is enhanced in modern nanodevices as they can be fabricated practically defect free with near ballistic levels of operation. In contrast with ChemFETs, where one detects a single threshold shift for a specific molecule, here we get an entire spectral nano-‘barcode’ that can be compared against a compilation of theoretical responses to characterize and sense a molecular species. Since these devices operate by modulating surface properties of transistors, we call them 'SurfFETs'. The significant advantage of such SurfFETs is their exclusive detection of only molecules that overlap significantly with the channel to cause a transfer of states. This means that this electronic detection scheme is selective and inherently avoids false positives- clearly an advantageous feature for detection of molecules.