suspended CVD graphene
In this new publication, entitled: Highly symmetric and tunable tunnel couplings in InAs/InP nanowire heterostructure quantum dots Frederick and co-worker show that built-in quantum dots (QD) are very versatile for high resolution tunneling spectroscopy,
since the tunnel coupling strength G1 and G2 can be tuned between micro and milli-Volts simply by changing the charge state of the QD. The QD charge state is controlled by a gate voltage and can be raised from pinch-off (zero charges) to seveal hunderds of electrons on the QD. Moreover, it is found that the grown barriers are highly symmetric. We have obtained these amazing nanowires from the CNR-NANO group of Prof. Lucia Sorba, grown by Valentina Zannier.
Below we reprouce a short section of the “charge-stability diagram”, where the vertical axis corresponds to the applied source-drain bias from -10 to +10 mV and the vertical axis to the gate voltage from +10 to 20V. Pinch-off is at around 0V at the gate and the QD can be loaded to up to +40V, corresponding to ~200 electrons on the QD. The bottom figure is a zoom the left part. Up to a few vissible gate-jumps these QDs are very stable adnd can be measured over weeks.