Letters to Nature

Nature 392, 160-162 (12 March 1998) | doi:10.1038/32373; Received 14 August 1997; Accepted 29 December 1997

A nanometre-scale mechanical electrometer

A. N. Cleland2 & M. L. Roukes1

  1. Condensed Matter Physics 114-36, California Institute of Technology, Pasadena, California 91125, USA
  2. Present address: Department of Physics, UC Santa Barbara, Santa Barbara, California 93106, USA.

Correspondence to: M. L. Roukes1 Correspondence and requests for materials should be addressed to M.L.R. (e-mail: Email: roukes@caltech.edu).

The mechanical detection of charge has a long history, dating back more than 200 years to Coulomb's torsion-balance electrometer1. The modern analogues of such instruments are semiconductor-based field-effect devices, the most sensitive of which are cryogenically cooled single-electron transistors2. But although these latter devices have extremely high charge sensitivity, they suffer from limited bandwidth and must be operated at millikelvin temperatures in order to reduce thermal noise. Here we report the fabrication and characterization of a working nanometre-scale mechanical electrometer. We achieve a charge sensitivity of 0.1 e Hz-0.5, competitive with conventional semiconductor field-effect transistors; moreover, thermal noise analysis indicates that the nanometre-scale electrometer should ultimately reach sensitivities of the order of 10-6 e Hz-0.5, comparable with charge-detection capabilities of cryogenic single-electron transistors. The nanometre-scale electrometer has the additional advantages of high temperature (greater than or equal to4.2 K) operation and response over a larger bandwidth, from which a diversity of applications may result.