Growth of uniformly distributed Ru nanocrystals on Al2O3 is demonstrated via atomic layer deposition using bis(cyclopentadienyl)-ruthenium and oxygen precursors. X-ray photoelectron spectroscopy analyses reveal that metallic Ru nanocrystals were formed in this experiment, and the RuO2 surface is due to oxidation of Ru when exposed to air. The metal-oxide-silicon capacitors with Ru nanocrystals embedded into Al2O3 are electrically measured, exhibiting obvious memory effects such as a large hysteresis memory window of 3.4 V for the sweeping gate voltage of −2.5/ + 8 V and a significant flat-band voltage shift of 3.2 V under the programming of 10 V/1 ms, i.e. an effective electron injection rate as fast as 1.78 × 10−6 C cm−2 ms−1. This relates to the program mechanism of direct tunnelling and a large potential well depth.

Benefitting from the antenna effect and localized surface plasmon resonance (LSPR), a metal nanoparticle with a designed morphology has the amazing ability to confine light energy into the required extremely small volume, whose refractive index largely affects the optical properties of the whole metal nanoparticle. In this work, the optical spectra and near-field distribution of a gold nanocrescent array were investigated both experimentally and theoretically. To find out the LSPR wavelength and the enhancement using different morphologies of sharp tips, the spectra of gold nanocrescent arrays with different waist widths (d) were first measured, which were then confirmed and analyzed using the finite difference time-domain method and the hybridization theory. At last, the LSPR of this array with 100 nm diameter dielectric nanodisks was studied for sensing in subwavelength areas. Our results showed that because of its giant nanoantenna-enhanced electromagnetic field at the two tips, this gold nanocrescent array could be a suitable local senor to sense the variation of a local medium in a subwavelength area.

The Fano resonance induced by symmetry breaking could improve the sensitivity of localized surface plasmon resonance sensors. In this work, the spectra of gold nanocrescent arrays are measured and confirmed by simulation results through the finite element method (FEM). The Fano resonance presented in the spectra could be modulated by the symmetry breaking with different waist widths, which are understood through plasmonic hybridization theory with the help of surface charge distribution. Our results indicate the Fano lineshape is generated by the coherent coupling of the quadrupole plasmon mode Q_H of nanohole and the antibonding plasmon mode D(AB) of nanocrescent. Finally, the high figure of merit (FoM=1.6-3.5) of the Q mode in the visible region illustrates this nanocrescent Fano sensor is of great value in the biological and chemical scientific fields.

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Charge trapping characteristics of the metal-insulator-silicon (MIS) capacitors with SiO2/HfO2/Al2O3 stacked dielectrics are investigated for memory applications. A capacitance-voltage hysteresis memory window as large as 7.3 V is achieved for the gate voltage sweeping of ±12 V, and a flat-band voltage shift of 1.5 V is observed in terms of programming under 5 V and 1 ms. Furthermore, the time-and voltage-dependent charge trapping characteristics are also demonstrated, the former is related to charge trapping saturation and the latter is ascribed to variable tunnelling barriers for electron injecting and discharging under different voltages.