A micromechanical electrometer approaching single-electron charge resolution at room temperature

We report a MEMS electrometer with a measured charge noise floor approaching the single-electron threshold (4 e/radicHz) in air at room temperature. The electrometer is based on a modulated capacitor constructed from a micromechanical resonator, which converts DC charge at the input to an output AC voltage with primary frequency components at twice the modulation frequency. The result presented herein confirms earlier results obtained through analytical modeling and provides a path towards achieving sub-electron charge resolution at room temperature.