Ge Epitaxy at Ultralow Growth Temperatures Enabled by a Pristine Growth Environment.

Germanium (Ge), the next-in-line group-IV material, bears great potential to add functionality and performance to next-generation nanoelectronics and solid-state quantum transport based on silicon (Si) technology. Here, we investigate the direct epitaxial growth of two-dimensional high-quality crystalline Ge layers on Si deposited at ultralow growth temperatures ( = 100-350 °C) and pristine growth pressures (≲10 mbar). First, we show that a decreasing does not degrade the crystal quality of homoepitaxial Ge/Ge(001) by comparing the point defect density using positron annihilation lifetime spectroscopy.

Role of en-APTAS Membranes in Enhancing the NO Gas-Sensing Characteristics of Carbon Nanotube/ZnO-Based Memristor Gas Sensors.

NO is a toxic gas that can damage the lungs with prolonged exposure and contribute to health conditions, such as asthma in children. Detecting NO is therefore crucial for maintaining a healthy environment. Carbon nanotubes (CNTs) are promising materials for NO gas sensors due to their excellent electronic properties and high adsorption energy for NO molecules.

Terahertz Radiation Driven Nonlinear Transport Phenomena in Two-Dimensional Tellurene.

Nonlinear electron transport induced by polarized terahertz radiation is studied in two-dimensional tellurene at room temperature. A direct current, quadratic in the radiation's electric field, is observed. Contributions sensitive to radiation helicity and polarization orientation as well as polarization independent current are found.

Ferroelectric Polarization Coupling Effect in BiFeO/α-InSe Ferroelectric Field Effect Transistor for Stable Non-volatile Memory.

Ferroelectric field-effect transistors (FeFETs) commonly utilize traditional oxide ferroelectric materials for their strong remanent polarization. Yet, integrating them with the standard complementary metal oxide semiconductor (CMOS) process is challenging due to the need for lattice matching and the high-temperature rapid thermal annealing process, which are not always compatible with CMOS fabrication. However, the advent of the ferroelectric semiconductor α-InSe offers a compelling solution to these challenges.

Low-Temperature Lithium Metal Batteries Achieved by Synergistically Enhanced Screening Li Desolvation Kinetics.

Lithium metal anode is desired by high capacity and low potential toward higher energy density than commercial graphite anode. However, the low-temperature Li metal batteries suffer from dendrite formation and dead Li resulting from uneven Li behaviors of flux with huge desolvation/diffusion barriers, thus leading to short lifespan and safety concern. Herein, differing from electrolyte engineering, a strategy of delocalizing electrons with generating rich active sites to regulate Li desolvation/diffusion behaviors are demonstrated via decorating polar chemical groups on porous metal-organic frameworks (MOFs).

Improving Energy Resolution of CdSe-Based γ-Ray Detectors through Asymmetric Schottky Contact Engineering Using Oxygen Plasma Treatment.

When creating a Schottky contact to suppress the leakage current of semiconductor γ-ray detectors and improve their energy resolution, it is successfully employed the fact that the formation of a Schottky barrier is determined not only by the difference in the electrode and semiconductor work functions but also affected by the semiconductor surface state. Oxygen plasma (OP) treatment has been used to modify the surface states of CdSe single crystals (SCs) prior to the Au electrode deposition, thereby creating a Schottky contact at the metal-semiconductor interface. The -type Schottky contact formation has been confirmed by the - characteristics and ultraviolet photoelectron spectroscopy analysis.

Continuous-wave electrically pumped multi-quantum-well laser based on group-IV semiconductors.

Over the last 30 years, group-IV semiconductors have been intensely investigated in the quest for a fundamental direct bandgap semiconductor that could yield the last missing piece of the Si Photonics toolbox: a continuous-wave Si-based laser. Along this path, it has been demonstrated that the electronic band structure of the GeSn/SiGeSn heterostructures can be tuned into a direct bandgap quantum structure providing optical gain for lasing. In this paper, we present a versatile electrically pumped, continuous-wave laser emitting at a near-infrared wavelength of 2.

Stable π Radical BDPA: Adsorption on Cu(100) and Survival of Spin.

The adsorption of the radical α,ɣ-bisdiphenylene-β-phenylallyl (BDPA) molecule to the Cu(100) surface was studied using scanning tunnelling microscopy (STM), scanning tunnelling spectroscopy (STS), and density functional theory (DFT) calculations accounting for dispersion forces. BDPA on Cu(100) was observed to align preferentially along directions due to weak Cu-C chemisorption between fluorenyl carbons with the underlying copper atoms. The curved shape of the BDPA molecule on Cu(100) can be ascribed to the lack of molecular orbital character on the phenyl substituent.

Polarization-resolved resonant Raman excitation of surface and bulk electronic bands and phonons in MBE-grown topological insulator thin films.

Interaction of phonons with Dirac-like electronic states sets the fundamental limit of electron transport in topological insulators (TIs). Polarization-resolved and resonant Raman scattering of bulk and surface electronic excitation and vibrational modes in BiTe and BiSbTeSe (BSTS) thin films was investigated. At photon energies () of 1.

Novel analysis tool for the distance of gold dimers controlled by the DNA strand length on the DNA origami.

Metallic nanoparticle dimers have been used to enhance the excitation rate of single-quantum emitters. The interparticle distance (d) of the dimers has a crucial influence on the signal enhancement. Therefore, precise control of d is desired for optimal performance.

Intermittent hypoxia-hyperoxia training ameliorates cognitive impairment and neuroinflammation in a rat model of Alzheimer's disease.

Alzheimer's disease (AD), characterized by severe and progressive cognitive decline, stands as one of the most prevalent and devastating forms of dementia. Based on our recent findings showing intermittent hypoxic conditioning improved neuronal function in patients with mild cognitive impairment, the present study aimed at investigating whether the neuroprotective effects of intermittent hypoxia can be replicated in a rat model of AD, which allows us to explore the underlying cellular mechanisms involving neuroinflammation, hypoxia inducible factor 1α (HIF1α), and cytochrome P450 family 2 subfamily E member 1 (CYP2E1). Forty-one adult male Wistar rats were randomly assigned to three groups: 1) Control group: received intracerebroventricular (ICV) injection of saline; 2) STZ group: received ICV injection of streptozotocin (STZ) to induce AD-like pathology; and 3) STZ + IHHT group received ICV injection of STZ as well as 15 daily sessions of intermittent hypoxia-hyperoxia training (IHHT).

Thermo-Convective Solution Growth of Vertically Aligned Zinc Oxide Nanowire Arrays for Piezoelectric Energy Harvesting.

The search for a synthesis method to create longer ZnO NWAs with high-quality vertical alignment, and the investigation of their electrical properties, have become increasingly important. In this study, a hydrothermal method for growing vertically aligned arrays of ZnO nanowires (NWs) using localized heating was utilized. To produce longer NWs, the temperature environment of the growth system was optimized with a novel reaction container that provided improved thermal insulation.

Bottom Electrode Modification Enables Efficient and Bright Silicon-Based Top-Emission Perovskite Light-Emitting Diodes.

The integration of perovskites with mature silicon platform has emerged as a promising approach in the development of efficient on-chip light sources and high-brightness displays. However, the performance of Si-based green perovskite light-emitting diodes (PeLEDs) still falls significantly short compared to their red and near-infrared counterparts. In this study, it is revealed that the high work function Au, widely employed in Si-based top-emission PeLEDs as the reflective bottom electrode, exhibits considerably lower reflectivity in the green spectrum than in the longer wavelengths.

Tuning the optical absorption and exciton bound states of germanene by chemical functionalization.

We present a comprehensive study of buckled honeycomb germanene functionalized with alternately bonded side groups hydroxyl (-H), methyl (-CH) and trifluoro methyl (-CF). By means of most modern theoretical and computational methods we determine the atomic geometries versus the functionalizing groups. The quasiparticle excitation effects on the electronic structure are taken into account by means of exchange-correlation treatment within the GW framework.

Enhancing the Resistive Switching Properties of Transparent HfO-Based Memristor Devices for Reliable Gasistor Applications.

We present a transparent memristor with a rough-surface (RS) bottom electrode (BE) with enhanced performance and reliability for a gasistor, which is a gas sensor plus a memristor, and its application in this paper. The transparent memristor, with an RS BE, exhibited low forming voltages (0.8 V) and a stable resistive switching behavior, with high endurance and an on/off ratio of about 125.

Irradiating the Path to High-Efficiency Zn-Ion Batteries: An Electrochemical Analysis of Laser-Modified Anodes.

Global energy consumption is increasing yearly, yet the world is trying to move toward carbon neutrality to mitigate global warming. More research is being done on energy storage devices to advance these efforts. One well-known and widely studied technology is Zn-ion batteries (ZIBs).

A dual-mode homogeneous electrochemical-colorimetric biosensing sensor for carcinoembryonic antigen detection based on a microfluidic paper-based analysis device.

Dual-mode-based sensors have drawn a lot of interest due to their high accuracy and sensitivity compared to single-response systems. A simple electrochemical and colorimetric dual-mode sensor based on enzyme-linked immunosorbent assay (ELISA), without complex electrode surface modification, was developed for accurate and sensitive detection of carcinoembryonic antigen (CEA). The target CEA is recognized by an antibody coupled to horseradish peroxidase (HRP), which then oxidizes the substrate 3,3',5,5'-tetramethylbenzidine (TMB) to generate both a colorimetric and an electrochemical signal.

Nanoheteroepitaxy of Ge and SiGe on Si: role of composition and capping on quantum dot photoluminescence.

We investigate the nanoheteroepitaxy (NHE) of SiGe and Ge quantum dots (QDs) grown on nanotips (NTs) substrates realized in Si(001) wafers. Due to the lattice strain compliance, enabled by the nanometric size of the tip and the limited dot/substrate interface area, which helps to reduce dot/substrate interdiffusion, the strain and SiGe composition in the QDs could be decoupled. This demonstrates a key advantage of the NHE over the Stranski-Krastanow growth mechanism.

Acoustically semitransparent nanofibrous meshes appraised by high signal-to-noise-ratio MEMS microphones.

Microelectromechanical system-based microphones demand high ingress protection levels with regard to their use in harsh environment. Here, we develop environmental protective components comprising polyimide nanofibers combined onto polyether ether ketone fabric meshes and subsequently appraise their impact on the electroacoustic properties of high signal-to-noise-ratio microelectromechanical system-based microphones via industry-standard characterizations and theoretical simulations. Being placed directly on top of the microphone sound port, the nanofiber mesh die-cut parts with an inner diameter of 1.