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Two-dimensional (2D) oxide perovskites show great promise as candidates for future optoelectronic devices. For the first time, we have successfully exfoliated 2D perovskite NdNb2O7(NNO) nanosheets by a solid-state calcination and liquid-phase exfoliation method. The individual NNO nanosheet photodetector (PD) demonstrates outstanding performance in detecting UV light (260nm, 3V), including high responsivity (62 AW−1), high detectivity (6.7*1012Jones), high spectral selectivity (R260/R400= 9000), fast response speed (0.1/7.8 ms) and long-term stability. Furthermore, through a simple interface self-assembly technique, we have successfully achieved orderly and flat films of NNO nanosheets. The resulting film exhibits high transparency (>75%) in the visible light range. The NNO film device demonstrates excellent performance after undergoing numerous bending tests. This work not only presents a new candidate for high-performance and high-stability UV photodetectors but also introduces a general exfoliation and assembly strategy.

Resistive random access memory (RRAM) is one of the most promising candidates as a next generation nonvolatile memory (NVM), owing to its superior scalability, low power consumption and high speed. From the materials science point of view, to explore optimal RRAM materials is still essential for practical application. In this work, a new material (Bi, Mn)Ox(BMO) is investigated and several key performance characteristics of Pt/BMO/Pt structured device, including switching performance, retention and endurance, are examined in details. Furthermore, it has been confirmed by high-resolution transmission electron microscopy that the underlying switching mechanism is attributed to formation and disruption of metallic conducting nanofilaments (CNFs). More importantly, the power dissipation for each CNF is as low as 3.8/20fJ for set/reset process, and a realization of cross-bar structure memory cell is demonstrated to prove the downscaling ability of proposed RRAM. These distinctive properties have important implications for understanding switching mechanisms and implementing ultralow power-dissipation RRAM based on BMO.

We present an effective light extraction scheme for GaN-based multi-quantum-well (MQW) light emitting diodes with periodic SiO2nano-honeycomb arrays fabricated by natural lithography and reactive ion etching. The nano-honeycombs significantly boost light output by providing additional light extraction channels, not only guiding the internal modes into air but also alleviating the sever droop effect at high input power. At the driving current of 400mA, light output power through the nano-honeycombs is 77.8% higher than that of the bare device. In addition, the output power is particularly enhanced at the diffraction angle around 65°, which is attributed to the intensive first order diffraction on the honeycombs. Simulations based on finite-difference time-domain method are also carried out to reveal the field distribution across device interfaces.

We statistically demonstrated the electricity generation from individual vertically-aligned/epitaxial PbZr0.2Ti0.8O3(PZT) nanowires (NWs) using a conductive atomic force microscope (AFM). The measured outputs were analyzed in reference to the theoretically calculated piezopotential distribution in a bent NW. Our results show that the performance of the PZT NWs for electricity generation is at the same level as that of ZnO NWs although the piezocoefficient of PZT is high, due to high relative dielectric constant of PZT. Systematic investigating piezoelectricity from single PZT NWs will be useful for optimizing the performance for PZT nanogenerator applications.