The controlled formation of dangling bond structures on a H-terminated silicon surface is the first step in an atomically precise method of fabrication of silicon quantum electronic devices. An ultrahigh vacuum scanning tunneling microscope (STM) tip is used to selectively desorb hydrogen atoms from a Si(100)-2 ×1:H surface by injecting electrons with the sample held at a positive bias voltage. The

Tuning the magnetoresistance behavior of heterostructures composed of nonmagnetic and ferromagnetic (FM) materials is crucial for improving their applicability in electronic and spintronic devices. In this study, we investigate whether the integration of organic layers to NiFe/Pt junctions can result in the modification of the magnetic moment of the FM layer using iron phthalocyanines (FePc) and copper

Using spectroscopic ellipsometry from the midinfrared (0.03 eV) to the deep ultraviolet (6.5 eV), the authors determined the thickness dependence of the dielectric function for ZnO thin layers (5–50 nm) on Si and quartz in comparison to bulk ZnO. They observed a small blueshift of the band gap ( ∼80 meV) in thin ZnO layers due to quantum confinement, which is consistent with a simple effective mass

The authors present the results of the photoluminescence characterization of three asymmetric triple quantum well (ATQW) systems. Each one contains three ultrathin CdSe quantum wells of 1, 2, and 3 monolayers (ML) thickness grown by atomic layer epitaxy between ZnSe separating barriers. Two systems have coupled QWs due to thin 5 nm thick ZnSe separating barriers, and the uncoupled system has 100 nm

A two-dimensional electron gas (2DEG) is absent in ultrapure GaN/Al0.06Ga0.94N heterostructures grown by molecular beam epitaxy on bulk GaN at 300 K and in the dark. However, such a 2DEG can be generated by UV illumination and persists at low temperature after blanking the light. Under steady UV illumination as well as under persistence conditions, pronounced quantum transport with Shubnikov–de Haas

Novel ohmic contacts to n-ZnSe are demonstrated using single crystal Al films deposited on epitaxially grown ZnSe (100) by molecular beam epitaxy. Electron backscatter diffraction confirmed the single crystalline structure of the Al films. The (110)-oriented Al layer was rotated 45 ° relative to the substrate to match the ZnSe (100) lattice constant. The as-grown Al-ZnSe contact exhibited nearly ideal

The modification of optical and electronic properties of transition metal dichalcogenides via mechanical deformation has been widely studied. Their ability to withstand large deformations before rupture has enabled large tunability of the bandgap, and further, the spatially varying strain has been shown to control the spatial distribution of the bandgap and lead to effects such as carrier funneling

Field-effect transistors (FETs) are powerful devices in the semiconducting electronics industry and their manufacturing forms the basis of countless electronic devices. Most contemporary FETs rely on inorganic materials, mainly silicon that uses conventional photolithography, etching, and deposition techniques in sophisticated and expensive clean-room environments. An alternative route to fabricating

To fabricate AlGaN-based ultraviolet (UV) vertical cavity surface-emitting laser diodes, a pair of distributed Bragg reflectors (DBRs) having a smooth surface is desired to have a high quality factor (Q). In this work, photoassisted chemical etching (PCE) was attempted to smoothen the - c ( 000 - 2 ) AlN surface after removing the sapphire substrate by means of the laser lift-off process. First, the

Fermi level pinning at Schottky barriers strongly limits the minimization of contact resistances in devices and thereby limits the scaling of modern Si electronic devices, so it is useful to understand the full range of behaviors of Schottky barriers. The authors find that some semiconductor interfaces with compound metals like silicides have apparently weaker Fermi level pinning. This occurs as these

An underexposure photolithography method was developed to fabricate self-detached polymer micropore membranes with uniform pore size, shape, and arrangement. The key to this technique is to control and adjust the gradient of exposure dose projected into the film of photoresist. This new approach abandons sacrificial layers used in previous techniques. Negative SU-8 was chosen as an example photoresist

Focused ion beam (FIB) processing has been established as a well-suited and promising technique in R&D in nearly all fields of nanotechnology for patterning and prototyping on the micro- and nanometer scale and below. Among other concepts, liquid metal alloy ion sources (LMAISs) are one of the alternatives to conventional gallium beams to extend the FIB application field. To meet the rising demand

This report presents the results of fabricating GaN nanorods by inductively coupled plasma etching using BCl 3/Cl 2 chemistry. Interestingly, the GaN nanorods are formed only in the area initially masked by the sacrificial metal mask. In addition to the metallic mask, a specific feature of this process is the application of an insulating ceramic carrier for the improvement of the process performance

The molecular arrangement and electronic properties of submonolayer coverages of cobalt phthalocyanine (CoPc) molecules on the deactivated B-Si(111)- 3 × 3 R 30 ° surface are analyzed using scanning tunneling microscopy and spectroscopy. On the ideal surface, the dangling bonds, which typically prevent an ordered growth of molecules on semiconductors, are removed. However, the presence of single defects

Arc-discharge synthesized multiwalled carbon nanotubes (AD-MWNT), or related MWNTs, exhibit a good quality compared to the more common type of MWNT synthesized by catalytic chemical vapor deposition methods. Yet experimental measurements on these are rather few and typically have not correlated data from different measurement techniques. Here, the authors report Raman spectroscopy, scanning probe microscopy

We investigated the mechanism of premature etch stop in magnetic tunnel junction (MTJ) patterning using CO/NH3 plasma with a Ta mask to clarify the cause of etch-stop problem in high-density patterning due to mask deposition to a bottom space of a pattern. CO/NH3 plasmas consist of carbon monoxide, nitrogen, and hydrogen plasmas. To clarify the role of gas species in inducing this premature etch stop

Shaped emitters are of interest to a broad range of applications in vacuum electronic devices. In particular, thermionic energy converters (TECs) take advantage of shaped emitters to increase the local surface field, thereby extracting more current for a given cathode temperature and applied voltage. However, modeling these devices is challenging; Warp [J.-L. Vay, D. P. Grote, R. H. Cohen, and A. Friedman

A novel device consisting of a set of membranes with nine different geometries and metallizations monolithically fabricated on a single die is proposed as a possible calibration sample for characterizing thermal conductance between the tip and the sample with “active” resistive scanning thermal microscope (SThM) probes. Such probes, in which the tip is significantly heated by the current used to measure

Nanostructured multitip surfaces have sufficient potential to obtain the high emission currents necessary to develop stable and noninertial sources of free electrons with increased levels of permissible currents. The key to understanding the processes of formation and stability of macroscopic emission currents from these large area field emitters (LAFEs) is assessing the local characteristics of individual

High-current electron field emitters are of interest for many applications, but state-of-the-art devices suffer from limitations such as high turn-on macroscopic field, low macroscopic current density, poor emission stability, and short lifetime. Field emitter arrays with a high spatial density of uniform emitters have the potential to address these problems. This work presents the process development

Two-color resonant laser ionization sputtered neutral mass spectrometry offers high elemental selectivity. In this study, two-color resonance ionization in sputtered neutral Sr was confirmed by combining a grating type Ti:sapphire laser system and a time-of-flight secondary ion mass spectrometry (TOF-SIMS) system. The authors compared the ionization efficiencies of Sr of the two-color three-photon

The optimum detection levels that can be achieved by a secondary ion mass spectrometer are dependent on how efficiently a particular species of interest can be ionized and detected. One can determine in advance whether the analysis of a particular ion in the sample is possible, if the useful ion yield is known. The useful ion yield depends on the element, instrument transmission, the analytical conditions

In order to investigate the different role of kinetic and potential projectile energy for secondary ion formation, the authors have measured the ionization probability of indium atoms sputtered from a clean indium surface under irradiation with rare gas (Xeq+) ions of different charge states q at the same kinetic impact energy of 20 keV. In this energy range, the kinetic energy of the projectile is

In the framework of the development of back-side illuminated CMOS image sensors, high-resolution synchrotron tomography has demonstrated a proportionality between electromigration-induced void volumes and time-to-failure in hybrid bonding-based test structures. A new sample preparation workflow has allowed to employ synchrotron-based tomography for statistical studies and to make it a tool for routine

The timing of important events in the early history of the solar system can be established by using the decay of the short-lived radionuclide 53Mn to stable 53Cr. Carbonate minerals found in meteorite samples can be dated using this system provided that an accurate and precise value for the Mn/Cr ratio can be established. However, the ion yields of Mn and Cr vary substantially based upon the elemental

Visible light and secondary ions emitted from various sample surfaces (Si, HOPG, Cu, and Teflon) were observed after irradiation with highly charged ions (HCIs). HCIs were produced using an electron beam ion source (Kobe EBIS) at Kobe University. Visible emissions were detected using a liquid nitrogen cooled CCD detector. The mass spectrum of secondary ions was obtained using a quadrupole mass analyzer

In this work, thin epitaxial layers of dielectric barium titanate (BaTiO3 or BTO) were grown on Nb-doped strontium titanate (001) substrates using either molecular beam epitaxy or atomic layer deposition and then electrically stressed to the point of breakdown. The BTO layer thicknesses were in the range of 20–60 nm, and typical breakdown fields were in the range of 1.5–3.0 MV/cm. Electron microscopy

Andromede is a new instrument for mass spectrometry analysis of nanodomains and nano-objects present on a surface. The molecular sample information (mass and structure) is obtained from time-of-flight spectra of secondary ions emitted under the impact of nanoparticles (NPs), as A u n q + with n/q up to 200 accelerated by a 4 MV single stage electrostatic Pelletron® accelerator. Such projectiles, providing

This work considers the possible occurrence of two distinct phases in thin films of overall composition B1−xNx (0.21 ≤ x ≤ 0.47) grown by chemical vapor deposition from sequential pulses of diborane (B2H6) and ammonia (NH3). Two distinct peaks are identified in B1s x-ray photoelectron spectroscopy (XPS), related to two populations of B atoms with different oxidation states. The data are most consistent

Clearance mass flows are a major loss mechanism in dry running rotatory positive displacement vacuum pumps. Therefore, a detailed knowledge of the clearance mass flow is crucial to calculate the operation of those pumps. The small clearance heights and the large pressure range of such pumps require a wide range of gas rarefaction parameters to be taken into account. The flow in the clearance can be

A heterostructure containing several sheets of CdSe fractional monolayer quantum dots with nominal coverages of 0.5 and close to 0.25 of a monolayer (ML) embedded in a ZnSe matrix was successfully grown by a combination of submonolayer epitaxy and molecular beam epitaxy. Due to surface reconstruction properties of cation- and anion-terminated surfaces, one complete Cd–Se alternate source exposure cycle

Van der Waals layered GeTe/Sb2Te3 chalcogenide superlattices have demonstrated outstanding performance for use in dynamic resistive memories in what is known as interfacial phase change memory devices due to their low power requirement and fast switching. These devices are made from the periodic stacking of nanometer thick crystalline layers of chalcogenide phase change materials. The mechanism for

In this paper, the properties of Pd-based p-contacts on GaN-based laser diodes are discussed. Pd is often the metal of choice for ohmic contacts on p-GaN. However, for Pd/p-GaN ohmic contacts, nanovoids observed at the metal/semiconductor interface can have a negative impact on reliability and also reproducibility. The authors present a thorough analysis of the microstructure of the Pd/p-GaN interface

Managing the interaction of materials with insertion layers and nonconventional molecular beam epitaxy growth conditions allows for interfaces that are more precise but requires judicious examination of the multiple possible design variables. Here, we show a comparison between As- and Sb-containing insertion layers between Al and two binaries with different group V elements and demonstrate that antimonide

Recently, chalcogenide materials have exhibited ovonic threshold switching characteristics, improving their suitability as selector devices to effectively depress the sneak current in the cross-point array (CPA) structures. However, chalcogenides must be subjected to a firing process before they can exhibit the threshold switching behavior. The firing process causes operation problems with respect

AlN/GaN double-barrier resonant tunnel diodes have been grown by rf-plasma assisted molecular beam epitaxy at temperatures between 760 and 860 °C on metalorganic chemical vapor deposition-grown GaN templates with sapphire substrates. Room temperature negative differential resistance (NDR) was observed for all samples despite the presence of higher densities of threading dislocations in the device layers

Nanoimprint lithography (NIL) is one of the most promising nanofabrication techniques. Soft NIL has inherent advantages for conformal contact and uneven substrates. The demolding process of soft NIL is critical for obtaining high-fidelity replicas, especially of multidirectional nanostructures. In this paper, a demolding device for soft NIL is proposed to separate the polymer replica from the mold

Block copolymer (BCP) directed self-assembly (DSA) has been presented as a potential economically attractive enhancement to extend the capabilities of optical lithography for semiconductor manufacturing. One concern in DSA is the level of defectivity that can be achieved in such a process. Although entropic effects will always lead to some degree of defectivity, highly ordered structures with a low

The authors propose the use of a low-energy (sub-keV/atom) bismuth cluster ion beam for time-of-flight secondary ion mass spectrometry (TOF-SIMS). 2 keV Bi3+ at an incident angle of 65° generated bismuth-adducted secondary molecular ions [M + Bi]+, which are not observed under normal TOF-SIMS conditions. This low-energy Bi primary ion beam was used for the depth profiling of Irganox1010/Irganox1098

The authors drive a plasma-induced reduction reaction of the gold precursor by alternating current (AC)-driven atmospheric pressure plasma at the plasma-liquid interface. They systematically study the plasma-induced reaction at the plasma-liquid interface and observe that the reduction reaction is a proportionality relationship to the root mean square current of AC-driven atmospheric pressure plasma

Field emission scanning probe lithography (FE-SPL) is based on the exposure of a resist covered substrate with low energy electrons emitted from an ultra-sharp tip placed in close vicinity to a sample. GaN nanowires (NWs) present high mechanical stability, suitable geometry for FE-SPL, and controllable electrical properties achieved by adjusting dopant concentration. Here, the authors will present

The effect of metallic Mg insertion into the CoFeB/MgO/CoFeB-based magnetic tunnel junction (MTJ) on tunnel magnetoresistance (TMR) properties was investigated using synchrotron x-ray diffraction (XRD) in the out-of-plane geometry. For the MTJ without metallic Mg insertion, both low resistance area product (RA) and TMR ratio tend to decrease as the MgO barrier becomes thinner. When the 0.1-nm-thick

The apparent improvement of the depth resolution in secondary ion mass spectrometry depth profiles using cluster secondary ions (Me2+, Me3+) as compared to single ion profiles (Me+) is explained to be an artifact caused by an attractive interaction enhancing cluster formation. Successful application of the mixing-roughness-information depth model shows how different profiles are interconnected and

A new laser ionization method for sputtered neutral mass spectrometry (SNMS), which the authors call “dual-laser SNMS,” was developed to increase the ionization probability and improve sensitivity. In this technique, pulsed IR and UV lasers irradiated sputtered atoms simultaneously, while the additional UV laser pulse enhanced the ionization process. The useful yields of the target elements increased

Using ellipsometry for curved-surface characterization requires the knowledge of the surface normal vector in order to determine material-related surface parameters like refractive index, layer thickness, or birefringence of the surface material at the incidence point, because the recorded signal depends on both the (unknown) surface normal vector n → and material-related surface characteristics. It

The biggest advantage of time-of-flight secondary ion mass spectrometry (TOF-SIMS) is imaging performance. TOF-SIMS is the only surface analysis technique which can provide the elemental and molecular ion images with high spatial resolution and high sensitivity. However, acquiring accurate images of uniform intensity from three-dimensional (3D) objects having curved surfaces is challenging because

Secondary ion emission with MeV heavy ions provides a unique opportunity for insight into ion collisions and material analysis. MeV-energy ion beams excite electrons near the surface and enhance the ionization of high-mass molecules, enabling the acquisition of secondary ion mass spectrometry (SIMS) spectra of ionized molecules with suppressed fragments. The SIMS technique with MeV-energy heavy ions

The authors present a quantitative secondary ion mass spectrometry (SIMS) analysis of the useful ion yield of magnesium dopant in a gallium nitride matrix. A quadrupole SIMS instrument was used to analyze an Mg-doped GaN sample grown by metal organic chemical vapor deposition. Oxygen (O2+) was used as the primary ion beam and its energy was varied in the range from 0.5 to 5 kV with and without oxygen

Hydrogen behavior in tantalum and tantalum oxide thin films was examined using the in situ oxidation secondary ion mass spectrometry (in situ oxidation SIMS) method previously developed by the authors. Oxidation of Ta films by the introduction of O2 into the sputter deposition chamber immediately after film growth was found to reduce the amount of H absorbed in the Ta films by 2.7 times for samples

Due to their electrical and physical properties, Si1−XGeX materials are widely used in microelectronic devices. In particular, the Ge component found within Si1−XGeX compounds is important for enhancing carrier mobility and altering the lattice constant of metal-oxide-semiconductor field-effect transistors. In this study, magnetic sector secondary ion mass spectrometry (magnetic sector SIMS) and time-of-flight

Self-aligned double patterning (SADP), or spacer lithography, is a widely used technique in the semiconductor industry for high-throughput nanoscale pattern definition and thus is of great significance for very-large-scale integration, large-area photonic device fabrications, and other applications. In a standard SADP flow, chemical vapor deposition or atomic layer deposition is used to deposit a conformal

In nanoimprint lithography, a release agent on the mold surface is usually necessary for easy demolding between the mold and the imprinted (thermal) resist. In this work, the thermal stability of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) monolayers is studied using x-ray photoelectron spectroscopy. The FDTS monolayers are deposited on Si (100) substrates via vapor phase reactions. Significant

The use of any materials in particle accelerators requires a rigorous evaluation of their behavior in vacuum, especially when used at cryogenic temperatures. Laser treated copper substrates offer unquestionable advantages for electron-cloud mitigation purposes due to their low secondary electron yield. Here, the author investigates their vacuum behavior for the occurrence of small temperature transients

Recent studies have shown that it is possible to use ToF-SIMS to identify and quantify mosquito insecticides, such as permethrin and deltamethrin, on mosquito netting. The insecticide in those studies was incorporated in the netting fiber. Permethrin treated fabric is in common usage to provide mosquito repellent clothing and is the only approved insecticide for apparel. The insecticide is applied

Chemical imaging, such as mass imaging, provides a distribution image of a particular matter and is crucial for analyzing the chemical and physical mechanisms of a sample. However, methods that provide molecular or elemental distribution do not always have sufficiently high spatial resolution to evaluate the nanosized structures in a sample. To address this issue, a multimodal data analysis method

Although germanium (Ge) is a semiconductor frequently used in many facets of materials science, its optical applications are limited because of an indirect band structure, which significantly diminishes absorption and emission efficiency. However, sufficiently high levels of tin (Sn) alloying enable an indirect-to-direct band structure crossover, resulting in improved optical properties. Moreover,

Polypyridine-based ruthenium complexes are among the most interesting photoactive molecular systems, in virtue of a number of outstanding (photo)physicochemical properties. To exploit such properties in solid-state applications, such as molecular electronics, optoelectronics, and photovoltaics, tailored experimental strategies are needed for the anchoring of such complexes on surfaces. At the same

To facilitate the design of heterostructure devices employing hexagonal (sp2) boron nitride, x-ray photoelectron spectroscopy has been used to determine the valence band offsets (VBOs) at interfaces between amorphous hydrogenated sp2 boron nitride (a-BN:H) and atomic-layer-deposited high-dielectric-constant (high-k) aluminum oxide (Al2O3) and hafnium oxide (HfO2). After consideration of the effects

The demand for new biomaterials in several biomedical applications, such as regenerative engineering and drug delivery, has increased over the past two decades due to emerging technological advances in biomedicine. Degradable polymeric biomaterials continue to play a significant role as scaffolding materials and drug devices. Polyphosphazene platform is a subject of broad interest, as it presents an

The authors study the effect of etch chemistry and metallization scheme on recessed Au-free Ohmic contacts to AlGaN/GaN heterostructures on silicon. The effect of variation in the recess etch chemistry on the uniformity of Ohmic contact resistance has been studied using two different etch chemistries (BCl3/O2 and BCl3/Cl2). Experiments to determine the optimum recess etch depth for obtaining a low