My PhD work was in quantum devices and semiconductor nanostructures, including quantum dots, quantum point contacts, and 2D materials. My skills are in cryogenic engineering (including helium dilution cryostats), semiconductor fabrication, quantum device design, electron-beam lithography, nanoscale characterization (such as SEM, AFM, etc.), and instrument control & data analysis in Python.

As a quick primer of my work: solid state physics relies on models that treat materials by their free electrons. So while real materials are made up of atoms (made up of electrons, protons, and neutrons), it is simpler and sufficiently effective to consider only a subset of the electrons. Modern techniques allow us to create smaller and smaller semiconductors, until there is just a handful of free electrons available (called a quantum dot). This behaves similarly to a single atom—but while real atoms are 0.1 nanometer in size, semiconductor quantum dots can be 10-100s of nanometers in size, making them much more manageable and controllable.

In an electrostatically-controlled semiconductor quantum dot, you can measure exactly when a single electron is added or removed. An example measurement is as follows:

The X-axis (V_p) controls the electrostatic environment, and each black diamond represents the difference of a single electron! This change is measured by a change in the conductance through the quantum dot.

In my research, I created electronic circuits that used nanoscopic elements like quantum dots to control the electron flow down to the single electron. I think of it like an obstacle course for electrons! I also figured out how to combine a semiconductor quantum dot with a small metallic island. Semiconductors have the desirable quality of being controllable by electric fields; metals have the desirable quality of being a large reservoir of electrons (which is also why they are unable to be controlled by electric fields). Combining these two in a hybrid quantum dot creates a uniquely controllable reservoir that can be used in nanoelectronic circuits. Here is an example micrograph of an early prototype of our one-micron hybrid dot:

This is a false-colored scanning electron micrograph of an early prototype hybrid quantum dot, which deposits a metallic island (colored yellow) precisely onto a semiconductor (blue). While it may look simple, this is six layers of fabrication with dozens of process steps!

Beyond this, I was involved in other projects on twisted bilayer graphene (a remarkable 2D material) and quantum phase transitions. My work in quantum point contacts is published here and my Google Scholar is available here.