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Silicon nanoparticle (Si-NP)-embedded silicon nitride (Si3N4) thin films have been synthesized by implantation of Si ions into Si3N4 thin films followed by high-temperature thermal annealing. With different implant dosage of Si ions, the concentration of Si-NPs has been varied in the Si3N4 matrix. By forming an Al/Si-NP-embedded Si3N4/p-Si structure, memory behavior was observed through charging-caused modulation in the device current. The current–voltage measurements were then conducted to study the carrier transport mechanism and thus to understand the origin of charging-induced variation in device resistance. It was found that the current exhibited a hopping-based conduction mechanism at low electric field. While at high electric field, a Frenkel–Poole (F–P) emission was found to dominate the current conduction. As a result, the charging-caused electron trapping under positive voltage in Si-NPs of the nitride film enhances the F–P emission, leading to a significant reduction in resistance. However, negative voltage-caused hole trapping suppresses the current conduction. The two-terminal devices based on such Si-NP-embedded Si3N4 thin films are promising to be used as charging-controlled memory devices.

Al-rich thin films are synthesized by radio-frequency magnetron sputtering, followed by thermal annealing at 500°C for different durations to form Al/Al-rich diodes. The annealing causes reactions at the Al-rich interface, leading to an increase in Al concentration in the interface region. As a result, the current conduction of the diode is significantly enhanced, which results in anomalous capacitance-voltage (C-V) characteristics. The anomalous behaviors can be eliminated by reconstructing the C-V curve based on a four-element circuit model. The resistance of the Al-rich layer extracted from the C-V reconstruction shows power-law voltage dependence correlated with the current-conduction measurement.

In this brief, quenching of electroluminescence (EL) from Si-implanted silicon nitride (SNR) thin film under a forward bias has been observed. The quenching phenomenon is shown to be due to charge trapping in the defect states involved in the radiative recombination. The composite EL bands have different quenching rates, causing a change in the EL spectrum shape by the EL quenching. Release of the trapped charges by a low-temperature annealing at 120degC or an application of a reverse gate bias can partially recover the quenched EL both in the intensity and spectrum shape. The quenching phenomenon poses a serious challenge to the application of Si-implanted SNR thin films in light-emitting devices.

Strong visible electroluminescence (EL) has been observed from a 30 nm silicon nitride thin film multiply implanted with Si ions and annealed at 1100 degree celcius. The EL intensity shows a linear relationship with the current transport in the thin film at lower voltages, but a departure from the linear relationship with a quenching in the EL intensity is observed at higher voltages. The EL spectra show two primary EL bands including the predominant violet band at ∼ 3.0 eV (415 nm) and the strong green-yellow band at ∼ 2.2 eV (560 nm). Two weak bands including the ultraviolet band at ∼ 3.8 eV and the near infrared band at ∼ 1.45 eV emerge at high voltages. The evolution of each EL band with the voltage has been examined. The phenomena observed are explained, and the EL mechanisms are discussed. Published version

In this work, Al2O3 thin film containing Al nanocrystals (nc-Al) is deposited on Si substrate by radio frequency sputtering to form a metal-insulator-semiconductor structure. Both electron and hole trapping in nc-Al are observed. The charge storage ability of the nc-Al/Al2O3 thin films provides the possibility of memory applications. Charging in the nc-Al also leads to a change in the dc resistance of the thin films, namely, the electron trapping in the nc-Al leads to an increase in the resistance, whereas the resistance is reduced if there is hole trapping in the nc-Al. Published version

Al nanocrystal (nc-Al)/Al2O3 nanocomposite thin films were synthesized by radio-frequency magnetron sputtering. The static dielectric constant (er) of the nanocomposite thin films was determined by the capacitance-voltage reconstruction technique which was able to correct for the influence of high current conduction in the thin films. In contrast to pure Al2O3, the nanocomposite has a much higher er and its er exhibits strong temperature dependence also. The higher er is attributed to the dipole effect of the Al–O dangling bonds due to the presence of nc-Al in the Al2O3 matrix. However, the dipole effect degrades at a higher temperature, which explains the observed decrease in er with increasing temperature.

In this letter, Ni-rich NiO thin film is deposited on p-type Si substrate by dc magnetron sputtering to form a metal-insulator-semiconductor structure. The charge trapping in the Ni nanocrystals (nc-Ni) embedded in NiO matrix induces a flatband voltage shift and capacitance modulation, which could be used for memory applications. The charging of nc-Ni depends on the voltage polarity, as well as the charging time and magnitude of gate voltage. The capacitance modulation can be described by an equivalent circuit model.

Anomalous capacitance-voltage (C-V) characteristics of Al/Al-rich Al2O3/p-Si capacitors have been observed. The measured C-V curves exhibit rolloffs and frequency dispersion in the accumulation region and voltage stresses cause both horizontal and vertical shifts of the C-V curves. These anomalous behaviors are mainly due to the large current conduction and the charge trapping in the Al-rich Al2O3 layer. The anomalous C-V characteristics have been reconstructed based on a four-element circuit model. With the reconstructed C-V curves, the capacitance of the Al-rich Al2O3 layer and the charging-induced flatband voltage shift can be determined.

Optical properties of implanted Si in a silicon nitride thin film have been determined with spectroscopic ellipsometry based on the Tauc–Lorentz (TL) model and the Bruggeman effective medium approximation. It is shown that the suppressed dielectric functions of the implanted Si are dominated by the energy transitions related to the critical point E2. The effect of thermal annealing on the dielectric functions of the implanted Si has been investigated. The analysis of the dielectric functions based on the evolution of the TL parameters can provide an insight into the structural changes in the implanted Si embedded in the Si3N4 matrix caused by the annealing. Published version

Al nanocrystals (nc-Al) embedded in AlN thin films have been synthesized by rf magnetron sputtering. The influence of ultraviolet (UV) illumination on electrical characteristics of the nc-Al/AlN thin film system has been investigated. It is shown that the UV illumination could lead to a random change in the conductance of the thin film system. The change in the conductance is attributed to the charge trapping and detrapping in the nc-Al due to the UV illumination. Published version