Publications Details

Sensing Few Electrons Floating on Helium with High-Electron-Mobility Transistors

Henry, David; Shaner, Eric A.; Lyon, Stephen A.; Liu, Lydia T.; Fuchs, Gordian; Feldman, Mayer M.

We report on low-frequency measurements of few electrons floating on superfluid helium using a bespoke cryogenic cascode amplifier circuit built with off-the-shelf GaAs high-electron-mobility transistors (HEMTs). We integrate this circuit with a charge-coupled device (CCD) to transport the electrons on helium and characterize its performance. Here, we show that this circuit has a signal-to-noise ratio (SNR) of ~ 2 $\frac{e}{√Hz}$ at 102 kHz, an order of magnitude improvement from previous implementations, and provides a compelling alternative to few electron sensing with high-frequency resonators.