Hybrid channel induced forming-free performance in nanocrystalline-Si:H/a-SiNx:H resistive switching memory.

The unique forming-free feature of Si-based resistive switching memory plays a key role in the industrialization of next generation memory in the nanoscale. Here we report on a new forming-free nanocrystalline-Si:H (nc-Si:H)/SiN:H resistive switching memory that can be obtained by deposition of hydrogen diluted nc-Si on hydrogen plasma treated a-SiN:H layer. It is found that nc-Si dots with areal density of 5.

Enhanced superconductivity of BaKFeAs under surface potassium dosing.

Surface potassium dosing has been proven to be an effective method in tuning the electron doping and enhancing the superconducting transition temperatures in both iron chalcogenides and electron doped iron pnictides. However, it is not clear how surface potassium dosing affects the hole doping and superconductivity in hole doped Fe-based superconductors. Here we performed K-dosing on BaKFeAs, a prototypical hole-doped iron pnictide compound, and explored the electronic structure by in situ angle-resolved photoemission spectroscopy measurements.

Directly probing the dissociation effects of graphene oxide nanosheets on hIAPP fibrils.

The aggregation of human islet amyloid polypeptides (hIAPP) to mature fibrils is considered as the main cause of type II diabetes. Therefore destroying the pre-formed hIAPP fibrils is expected to be a promising strategy for therapeutic treatments. In this work, the dissociation effects of graphene oxide (GO) nanosheets on hIAPP mature fibrils are investigated.

An electronic synaptic device based on HfOTiO bilayer structure memristor with self-compliance and deep-RESET characteristics.

We reported on a Ti/HfO/TiO/Pt memristor with self-compliance, deep-RESET characteristics and excellent switching performance, including ultrafast program/erase speed (10 ns), a large memory window (10) and good pulse endurance (10 cycles). The self-compliance and deep-RESET characteristics are beneficial for protecting the device from permanent breakdown in both SET and RESET processes especially under the pulse operation mode. In addition to bistable state switching, we also achieved multiple or even continuous conductance state switching under a DC sweep and a pulse-train operation mode in the Ti/HfO/TiO/Pt memristor, which can be seen as a substitution of a biological synapse.

Presetting conductive pathway induced the switching uniformity evolution of a-SiN:H resistive switching memory.

Si-based resistive random access memory (RRAM) devices at the nanoscale with high uniformity have great potential applications in the future. We demonstrate that the uniformity evolution of the a-SiN:H RRAM at the low resistance state (LRS) and the high resistance state (HRS) can be clearly monitored by presetting a Si dangling bond (Si-DB) conductive pathway through thermal energy. It is found that the increased magnitude of uniformity for the LRS and the HRS are determined by the number of preset Si-DBs, which can be controlled by tuning thermal energy.

Toward precise site-controlling of self-assembled Ge quantum dots on Si microdisks.

A feasible route is developed toward precise site-controlling of quantum dots (QDs) at the microdisk periphery, where most microdisk cavity modes are located. The preferential growth of self-assembled Ge QDs at the periphery of Si microdisks is discovered. Moreover, both the height and linear density of Ge QDs can be controlled by tuning the amount of deposited Ge and the microdisk size.

Forming-free performance of a-SiN :H-based resistive switching memory obtained by oxygen plasma treatment.

An a-SiN -based resistive random access memory (RRAM) device with a forming-free characteristic has significant potentials for the industrialization of the next-generation memories. We demonstrate that a forming-free a-SiN O RRAM device can be achieved by an oxygen plasma treatment of ultra-thin a-SiN :H films. Electron spin resonance spectroscopy reveals that Si dangling bonds with a high density (10 cm) are distributed in the initial state, which exist in the forms of SiN≡Si·, SiO≡Si·, O≡Si·, and N≡Si·.

Electrostatic effect of Au nanoparticles on near-infrared photoluminescence from Si/SiGe due to nanoscale metal/semiconductor contact.

Photoluminescence (PL) from Si and SiGe is comprehensively modified by Au NPs under excitation without surface plasmon resonance. Moreover, the PL sensitively depends on the size of the Au NPs, the excitation power and the thickness of the Si layer between the Au NPs and SiGe. A model is proposed in terms of the electrostatic effects of Au NPs naturally charged by electron transfer through the nanoscale metal/semiconductor Schottky junction without an external bias or external injection of carriers.

Promising features of low-temperature grown Ge nanostructures on Si(001) substrates.

High-quality Ge nanostructures are obtained by molecular beam epitaxy of Ge on Si(001) substrates at 200 °C and ex situ annealing at 400 °C. Their structural properties are comprehensively characterized by atomic force microscopy, transmission electron microscopy and Raman spectroscopy. It is disclosed that they are almost defect free except for some defects at the Ge/Si interface and in the subsequent Si capping layer.

Fabrication and ferromagnetism of Si-SiGe/MnGe core-shell nanopillars.

Si-Si0.5Ge0.5/Mn0.

Discovery of robust in-plane ferroelectricity in atomic-thick SnTe.

Stable ferroelectricity with high transition temperature in nanostructures is needed for miniaturizing ferroelectric devices. Here, we report the discovery of the stable in-plane spontaneous polarization in atomic-thick tin telluride (SnTe), down to a 1-unit cell (UC) limit. The ferroelectric transition temperature T(c) of 1-UC SnTe film is greatly enhanced from the bulk value of 98 kelvin and reaches as high as 270 kelvin.

μSR investigation of a new diluted magnetic semiconductor Li(Zn,Mn,Cu)As with Mn and Cu codoping at the same Zn sites.

We report the successful synthesis and characterization of a new type I-II-V bulk form diluted magnetic semiconductor (DMS) Li(Zn,Mn,Cu)As, in which charge and spin doping are decoupled via (Cu,Zn) and (Mn,Zn) substitution at the same Zn sites. Ferromagnetic transition temperature up to  ∼33 K has been observed with a coercive field  ∼40 Oe for the 12.5% doping level.

Transient currents of a single molecular junction with a vibrational mode.

By using a propagation scheme for current matrices and an auxiliary mode expansion method, we investigate the transient dynamics of a single molecular junction coupled with a vibrational mode. Our approach is based on the spinless Anderson-Holstein model and the dressed tunnelling approximation for the electronic self-energy in the polaronic regime. The time-dependent currents after a sudden switching on the tunnelling to leads, an abrupt upward step bias pulse and a step potential on the quantum dot are calculated.

The synthesis and characterization of 1 1 1 1 type diluted ferromagnetic semiconductor (La(1-x)Ca(x))(Zn(1-x) Mn(x))AsO.

We report the synthesis and characterization of a bulk form diluted magnetic semiconductor, (La(1-x)Ca(x))(Zn(1-y) Mn(y))AsO, with a layered crystal structure isostructural to that of the 1 1 1 1 type Fe-based high-temperature superconductor LaFeAsO and the antiferromagnetic LaMnAsO. With Ca and Mn codoping into LaZnAsO, the ferromagnetic ordering occurs below the Curie temperature T(c) ∼30 K. Taking advantage of the decoupled charge and spin doping, we investigate the influence of carrier concentration on the ferromagnetic ordering state.

Consistent picture of the octet-nodal gap and its evolution with doping in heavily overdoped Ba(1-x)KxFe₂As₂.

We investigate the pairing symmetry in heavily overdoped Ba(1-x)KxFe2As2 based on the spin-fluctuation mechanism. We propose a Fermi-patch mechanism that is different from the conventional Fermi-surface-nesting picture. The exotic octet nodes of the superconducting gap and the unusual evolution of the gap with doping observed by the recent experiments are well explained in a unified manner.

Electronic structure of a new layered bismuth oxyselenide superconductor: LaO0.5F0.5BiSe2.

LaO(0.5)F(0.5)BiSe(2) is a new layered superconductor discovered recently, which shows the superconducting transition temperature of 3.

Dual enhancement of light extraction efficiency of flip-chip light-emitting diodes with multiple beveled SiC surface and porous ZnO nanoparticle layer coating.

A porous ZnO nanoparticle layer coating composed of columnar ZnO nanoparticle piles and a multiple-beveled substrate was used to enhance the light extraction efficiency of GaN-based flip-chip light-emitting diodes (FC-LEDs), which were grown on high-purity SiC substrates. The SiC substrate was multiple-beveled by fabricating an 'X' pattern on the face of it, followed by a deposition of a porous ZnO nanoparticle layer on the 'X'-patterned surface. A porous ZnO nanoparticle layer was fabricated with gas phase cluster beam deposition in a glancing incidence.