High negative differential resistance in silicon quantum dot metal-insulator-semiconductor structure

Metal-insulator-semiconductor structures, comprised of silicon quantum dot films grown by plasma-enhanced chemical vapor deposition, were fabricated on Si wafers. The devices showed a negative differential resistance, as a result of the resonant tunneling and the very high peak-to-valley current ratios of 2240 under illumination and 390 in the dark at room temperature, which are much higher than the corresponding values of other Si tunneling devices. The peak voltage was reduced down to 1.9V by increasing the doping concentration of the wafer and reducing the device area. The structure shows promise for use in solid-state switch applications.