Atomistic modeling of nano-scale Field Effect Transistors made of low-dimensional materials for single biomolecule Sensing

With significant progress in CMOS technology, nano-scale Field-Effect Transistors (FETs) with dimensions down to a few nm can be manufactured nowadays. Also, novel low dimensional materials such as carbon nanotubes (CNT) or 2D materials are being actively investigated as replacement of silicon channel transistors. This has opened doors not just for better computing but also for areas like ultra-sensitive bio-sensing, e.g., for genomics and proteomics, where both the miniaturization and alternative materials are expected to improve the sensitivity and potentially allow for single biomolecule detection. Large-scale integration of arrays of nanoscale transistors could provide for massive parallelization and deliver a more complete view of a biological system at low cost. Several challenges still need to be tackled to achieve such a large-scale bio sensor chip.

At device level, fundamental understanding is needed to quantify the impact of quantum effects, and better transport properties of low-dimensional materials on the sensitivity. E.g., in a CNTFET, the biomolecule current modulation mechanism may be enhanced compared to less ballistic silicon devices. To capture the target biomolecules on the FET, the surface of the transistor needs to be functionalized with probe molecules that can bind with the target biomolecules floating around in the electrolyte solution. This surface functionalization and the binding can influence the sensitivity of the FET, which is important to understand to achieve a low limit of detection.