New methods for benchmarking in nanoelectronics: gaining statistical significance and measuring the density-dependent mobility of two-terminal devices.

I will present results from selective area growth (SAG) of nanowires and nanostructures which encourage new directions in benchmarking of nanoelectronic devices. Firstly, we show how incorporating multiplexing circuits directly on the sample enables the measurement of hundreds of nominally identical devices during the same measurement run. This brings statistical significance to measurements of important parameters such as mobility and threshold voltage, while also providing enhanced insights into the role of different scattering mechanisms and highlighting new physics. We also show how the reproducibility offered by SAG opens the possibility for scale-up of quantum devices, by demonstrating that gate-defined quantum dots could be induced in 20 different nanowires using only three shared crossbar gates.

In the second part of the talk, I will present a method for extracting the carrier density-dependent mobility of two-terminal devices at zero magnetic field. Mobility is perhaps the most important indicator of material/device quality and depends strongly on carrier density as different scattering mechanisms dominate at different densities. However, measuring mobility vs density for many nanodevices such as nanowires is not routinely done, since their quasi-1D nature makes it challenging or impossible to fabricate the requisite number of non-invasive contacts required for e.g. Hall effect measurements. Nevertheless, a two-terminal measurement of conductance vs gate-voltage on a field-effect transistor-like device in principle contains the same information regarding mobility as a Hall effect measurement, if three parameters are known or well estimated. We demonstrate the equivalence of our new method to the Hall effect using SAG nanodevices. We then outline methods for estimating the three important parameters to thereby extract carrier mobility as a function of density for a wide class of two-terminal nanodevices.