Conductive‐bridge random access memory (CBRAM) is considered a strong contender of the next‐generation nonvolatile memory technology. Resistive switching (RS) behavior in CBRAM is decided by the formation/dissolution of nanoscale conductive filament (CF) inside RS layer based on the cation injection from active electrode and their electrochemical reactions. Remarkably, RS is actually a localized behavior, however, cation injects from the whole area of active electrode into RS layer supplying excessive cation beyond the requirement of CF formation, leading to deterioration of device uniformity and reliability. Here, an effective method is proposed to localize cation injection into RS layer through the nanohole of inserted ion barrier between active electrode and RS layer. Taking an impermeable monolayer graphene as ion barrier, conductive atomic force microscopy results directly confirm that CF formation is confined through the nanohole of graphene due to the localized cation injection. Compared with the typical Cu/HfO2/Pt CBRAM device, the novel Cu/nanohole‐graphene/HfO2/Pt device shows improvement of uniformity, endurance, and retention characteristics, because the cation injection is limited by the nanohole graphene. Scaling the nanohole of ion barrier down to several nanometers, the single‐CF‐based CBRAM device with high performance is expected to achieve by confining the cation injection at the atomic scale.

Mercuric ion (Hg2+) is one of the most toxic and serious environment polluting heavy metal ions, which can be accumulated in human body through food chains and drinking water, and causes serious damage to human organs. Therefore, development of the efficient and sensitive method for detection of Hg2+ is very necessary. In this study, the high surface sensitivity and fingerprint information about the chemical structures based on surface‐enhanced Raman scattering (SERS) for sensing applications are taken advantage of. Au triangular nanoarrays/n‐layer graphene/Au nanoparticles sandwich structure with large‐area uniform subnanometer gaps are fabricated and used to detect Hg2+ in water via thymine–Hg2+–thymine coordination; the detection limit of Hg2+ is as low as 8.3 × 10−9m. Moreover, this SERS substrate is used to detect the Hg2+‐contaminated sandy soil and shows excellent performance. This study indicates the sandwich structure has a great potential in detection of toxic metal ions and environmental pollutants.

properties because of their special struc ture. When the materials reach a nano meter size, the electrical, optical, magnetic, and other properties of the materials will be altered greatly because of the small size effect, quantum size effect, sur face and boundary effects, and Coulomb blockade effect. [1] Currently, nanomaterials have been widely applied in many fields, including computers, catalysis, sensors, energy, and environmental protection. [2][3][4][5][6][7][8][9][10][11] As the demand increases, people aspire to fabricate nanomaterials with greater prop erties. Many methods have been used to improve the properties of nanomaterials, including doping, surface reconstruc tion, semiconductor composite, and metal nanoparticle embedding. [12][13][14][15][16][17][18][19][20] These days, ion beam techniques, including ion implantation, irradiation, and focused ion beam (FIB), have been extensively used to modulate the properties of nanomaterials. Moreover, ion beam techniques are regarded as a promising technique for doping and surface modification. Compared with doping during growth and diffusion, ion implantation is more controllable and reproducible. In addition, ion implantation is also an effective method for embedding nanoclusters in body materials. Moreover, ion irradiation is an effective method to modulate the morphology and surface structure of the mate rials. Therefore, via using this technique, various properties of nanomaterials can be tailored. FIB is typically used for the in situ study of ionirradiated materials. Figure 1 shows the applications of ion beam techniques for nanomaterial surface modification.Ion implantation, as an ion beam technique, has been extensively applied to the modulation of nanomaterial sur faces. Moreover, the technique has also been extensively used in the field of microelectronics. Ion implantation has replaced diffusion as a doping method to introduce dopants into the semiconductors. As an industrial technique, it exhibits high controllability and accuracy. In contrast to other doping strat egies, almost all elements can be introduced into the target materials by ion implantation and it does not introduce other impurity elements. In addition, ion implantation is not restricted by the solid solubility of elements in the mate rials. Ion implantation can be described as a collision process Nanomaterials have gained plenty of research interest because of their excellent performance, which is derived from their small size and special structure. In practical applications, to acquire nanomaterials with high performance, many methods have been used to modulate the structure and components of materials. To date, ion beam techniques have extensively been applied for modulating the performance of various nanomaterials. Energetic ion beams can modulate the surface morphology and chemical components of nanomaterials. In addition, ion beam techniques have also been used to fabricate nanomaterials, including 2D materials, nanoparticles, and nanowires. Compared with conventional metho...

Tungsten-graphene multilayer composites are fabricated using a stacking method. The thermal resistance induced by the graphene interlayer is moderate. An ion-implantation method is used to verify the radiation tolerance. The results show that graphene inserted among tungsten films plays a dominant role in reducing radiation damage. Furthermore, the performance of different tungsten period-thicknesses in radiation tolerance is systematically analyzed.

The ability to enhance the heat resistance of noble metals is vital to many industrial and academic applications. Because of its exceptional thermal properties, graphene was used to enhance the thermal stability of noble metals. Monolayer graphene-covered noble metal triangular nanoarrays (TNAs) showed excellent heat resistance, which could maintain their original triangular nanoarrays at high temperatures, whereas bare noble metal TNAs all agglomerate into spherical nanoparticles. On the basis of this mechanism, we obtained a universal recyclable surface-enhanced Raman scattering (SERS) substrate; after 16 cycles, the SERS substrate still worked well. The improvement of the heat resistance of noble metals by graphene has a great significance to the working reliability and service life of electronic devices and the single-use problem of traditional SERS substrates.

Conductive‐bridging random access memory (CBRAM), dominated by conductive filament (CF) formation/rupture, has received much attention due to its simple structure and outstanding performances for nonvolatile memory, neuromorphic computing, digital logic, and analog circuit. However, the negative‐SET behavior can degrade device reliability and parameter uniformity. And large RESET current increases power consumption for memory applications. By inserting 2D material, molybdenum disulfide (MoS2), for interface engineering with the device configuration of Ag/ZrO2/MoS2/Pt, the negative‐SET behavior is eliminated, and the RESET current is reduced simultaneously. With the ion barrier property of MoS2, the CF can probably not penetrate the MoS2 layer, thus eliminating the negative‐SET behavior. And with the low thermal conductivity of MoS2, the internal temperature of the device would be relatively high at RESET, accelerating probably redox reactions. As a result, the RESET current is reduced by an order of magnitude. This interface engineering opens up a way in improving the resistive switching performances of CBRAM, and can be of great benefit to the potential applications of MoS2 in next‐generation data storage.

The metal-oxide semiconductor TiO shows enormous potential in the field of photoelectric detection; however, UV-light absorption only restricts its widespread application. It is considered that nitrogen doping can improve the visible light absorption of TiO, but the effect of traditional chemical doping is far from being used for visible light detection. Herein, we dramatically broadened the absorption spectrum of the TiO nanowire (NW) by nitrogen ion implantation and apply the N-doped single TiO NW to visible light detection for the first time. Moreover, this novel strategy effectively modifies the surface states and thus regulates the height of Schottky barriers at the metal/semiconductor interface, which is crucial to realizing high responsivity and a fast response rate. Under the illumination of a laser with a wavelength of 457 nm, our fabricated photodetector exhibits favorable responsivity (8 A W) and a short response time (0.5 s). These results indicate that ion implantation is a promising method in exploring the visible light detection of TiO.

We report the thermal conductance induced by few-layered graphene (G) sandwiched between β-phase tungsten (β-W) films of 15, 30 and 40 nm thickness. Our differential characterization is able to distinguish the thermal conductance of β-W film and β-W/G interface. The cross-plane thermal conductivity (k) of β-W films is determined at 1.69~2.41 Wm−1K−1 which is much smaller than that of α-phase tungsten (174 Wm−1K−1). This small value is consistent with the large electrical resistivity reported for β-W in literatures and in this work. The β-W/β-W and β-W/G interface thermal conductance (G W/W and G W/G) are characterized and compared using multilayered β-W films with and without sandwiched graphene layers. The average G W/W is found to be at 280 MW m−2K−1. G W/G features strong variation from sample to sample, and has a lower-limit of 84 MW m−2K−1, taking into consideration of the uncertainties. This is attributed to possible graphene structure damage and variation during graphene transfer and W sputtering. The difference between G 2W/G and G W/W uncovers the finite thermal resistance induced by the graphene layer. Compared with up-to-date reported graphene interface thermal conductance, the β-W/G interface is at the high end in terms of local energy coupling.