Single strand DNA (ss-DNA) fragments act as negative potential gating agents that increase the hole density in graphene.
Patterning of biomolecules on graphene could provide new avenues to modulate the electrical properties. Current-voltage
characterization of this hybrid ss-DNA / graphene system indicates a shift of the Dirac point and "intrinsic" conductance
after ss-DNA is deposited. The effect of the ss-DNA is to increase the hole density in the graphene. The increased hole
density is calculated to be 2 × 1012 cm-2. This increase is consistent with the Raman frequency shifts in the G peak and
2D band positions and the corresponding changes in the G-peak full-width half maximum. Ab initio calculations using
density functional theory rule out significant charge transfer or modification of the graphene bandstructure in the
presence of the ss-DNA fragments.
InSb nanowire field effect transistors (NWFET) were fabricated using electrochemically synthesized nanowires. To
accurately extract transistor parameters, we introduced a model which takes into account the often ignored ungated
nanowire segments. A significant improvement in extracted device parameters was observed which demonstrated that
conventional models tend to underestimate the gate effect and therefore lead to lower carrier mobilities. Based on the
model, we obtained a NWFET ON current of 11.8uA, an ION/IOFF ratio of 63.5 and hole mobility of 292.84 cm2V-1s-1.