Metal-insulator-semiconductor (MIS) devices featuring silicon (Si) nanocrystals (NCs) embedded in a silicon dioxide (SiO2) insulating layer have been fabricated by radio frequency magnetron sputtering. Capacitance-voltage (C-V) curves of the Si:NC-MIS devices were found to exhibit deep depletion regions and frequency-dependent capacitance peaks at two values of bias voltage. Corresponding peaks were also identified in the conductance-voltage (G-V) curves of the Si:NC-MIS devices. The peaks are attributable to (i) the small signal response of interface states at the interface of the insulating layer and the Si substrate, and (ii) external inversion layer coupling in the transition region between the modes of tunnel-limited and semiconductor-limited electron current. (C) 2009 Elsevier Ltd. All rights reserved.