Hybrid organic-inorganic perovskites (HOIPs) exhibit long electronic carrier diffusion length, high optical absorption coefficient, and impressive photovol

Light emitting devices based on Si quantum dots/SiO₂ multilayers with dot size of 2.5 nm have been prepared. Bright white light emission is achieved under the dc driving conditions and the turn-on voltage of the device is as low as 5 V. The frequency-dependent electroluminescence intensity was observed under ac conditions of square and sinusoidal wave. It was found that the emission wavelength changes with frequency when sinusoidal ac is applied. The degradation of emission intensity is less than 12% after 3 h for ac driving condition, exhibiting the better device stability compared to the dc driving one.

We reported an Al ₂ O ₃ /HfO ₂ /Al ₂ O ₃ sandwich structure resistive switching device with significant improvement of multilevel cell (MLC) operation capability, which exhibited that four stable and distinct resistance states (one low resistance state and three high resistance states) can be achieved by controlling the Reset stop voltages ( V _Reset-stop ) during the Reset operation. The improved MLC operation capability can be attributed to the R _HRS / R _LRS ratio enhancement resulting from increasing of the series resistance and decreasing of leakage current by inserting two Al ₂ O ₃ layers. For the high-speed switching applications, we studied the initial switching dynamics by using the measurements of the pulse width and amplitude dependence of Set and Reset switching characteristics. The results showed that under the same pulse amplitude conditions, the initial Set progress is faster than the initial Reset progress, which can be explained by thermal-assisted electric field induced rupture model in the oxygen vacancies conductive filament. Thus, proper combination of varying pulse amplitude and width can help us to optimize the device operation parameters. Moreover, the device demonstrated ultrafast program/erase speed (10 ns) and good pulse switching endurance (10 ⁵ cycles) characteristics, which are suitable for high-density and fast-speed nonvolatile memory applications.

We propose a new self-limiting assembly model for Si quantum rings on Si(100) where the ring’s formation and evolution are driven by a growth-etching competition mechanism. The as-grown ring structure in a plasma enhanced chemical vapor deposition system has excellent rotational symmetry and superior morphology with a typical diameter, edge width, and height of 150–300, 10, and 5 nm, respectively. Based on this model, the size and morphology can be controlled well by simply tuning the timing procedure. We suggest that this growth model is not limited to certain material system, but provides a general scheme to control and tailor the self-assembly nanostructures into the desired size, shape, and complexity.

Memristors with tunable conductance characteristics have attracted great attention in high density memory and neuromorphic computing. However, the dynamics of conductance change for filamentary-type memristors is generally asymmetric: The set transition is quite abrupt, while the reset transition is usually gradual, which is a big challenge to achieve continuous conductance tuning characteristics in both set and reset processes. In this work, we demonstrated an HfO₂/TiO_x (10 nm/10 nm) bilayer structure memristor with the feature of bidirectional conductance tuning (a gradual increase or decrease in conductance) in a simple pulse-train operation mode. A series of voltage pulses with specific amplitude and a fixed width of 50 ns were used to realize the characteristics of bidirectional conductance tuning. By further optimizing the pulse amplitude conditions, such as −1.1 V/50 ns for the set process and 1.3–1.4 V/50 ns for the reset process, the conductance of the memristor can be tuned almost linearly with the input pulse voltage. Such linear conductance update is highly desired for improving the fault tolerance ability in massive data storage or neuromorphic computing.

Phosphorus (P) and Boron (B) co-doping effects at the nanoscale in Si nanocrystals/SiO₂ multilayers have been studied in the present work. Several interesting experimental results are achieved which are in contrast to the case in bulk-Si and the previous observations on the doped Si nanocrystals. It is found that all the co-doping samples are n-type regardless of B doping ratios. The P doping efficiency in Si NCs is higher than B dopants, and it can be improved via B co-doping with suitable levels. Raman and ESR spectra indicate that the different occupation preferences of P and B in Si NCs are responsible for the interesting co-doping behaviors. It looks like that the electronic structures and the physical properties of Si NCs can be modulated via the impurities co-doping approach.