A method of controlling a Casimir-effect device includes applying a voltage to a field-effect gate of the Casimir-effect device. The Casimir-effect device includes a conducting material and a semiconductor. The conducting material and semiconductor are separated by a gap to form the field-effect gate over at least a portion of the semiconductor facing the gap. The method further includes altering, in response to the applied voltage, a density of free charge carriers in the portion of the semiconductor facing the gap to control a nanoscale Casimir force between the conducting material and the portion of the semiconductor facing the gap.