We report the fabrication and measurement of silicon quantum dots with tunable tunnel barriers in a narrow-channel field-effect transistor. Low-temperature transport spectroscopy is performed in both the many-electron ( approximately 100 electrons) regime and the few-electron ( approximately 10 electrons) regime. Excited states in the bias spectroscopy provide evidence of quantum confinement. These results demonstrate that depletion gates are an effective technique for defining quantum dots in silicon.

A few-electron double quantum dot was fabricated using metal-oxide-semiconductor(MOS)compatible technology and low-temperature transport measurements were performed to study the energy spectrum of the device. The double dot structure is electrically tunable, enabling the interdot coupling to be adjusted over a wide range, as observed in the charge stability diagram. Resonant single-electron tunneling through ground and excited states of the double dot was clearly observed in bias spectroscopy measurements.

We report the demonstration of a silicon radio-frequency single electron transistor. The island is defined by electrostatically tunable tunnel barriers in a narrow channel field effect transistor. Charge sensitivities of better than 10 e / ͱ Hz are demonstrated at megahertz bandwidth. These results demonstrate that silicon may be used to fabricate fast, sensitive electrometers.