Abstract Long exposure dark-field micrographs have been imaged in weak but finite reflections from evaporated (III)-Au films normally considered forbidden on structure factor grounds. Contrast features the reflection images are attributed to single atomic steps film thickness, and used determine roughness of surface detail. The technique provides a powerful general method for studying thin surfaces.

Crystals of earth-abundant tin disulfide exhibit high-surface-area platelet formation with ideal photocatalytic properties for water splitting in their ground state.

Abstract Hexagonal boron nitride (h-BN) has been predicted to exhibit an in-plane thermal conductivity as high ~ 550 W m −1 K at room temperature, making it a promising management material. However, current experimental results (220–420 ) have well below the prediction. Here, we report on modulation of h-BN by controlling B isotope concentration. For monoisotopic 10 h-BN, 585 is measured 80% higher than that with disordered concentration (52%:48% mixture and 11 B). The temperature-dependent...

Abstract The structure of the NiSi2/(111)Si interface is investigated by lattice imaging (110) cross-sectional specimens in a JEOL 200CX transmission electron microscope with 2·4 Å point-to-point resolution. NiSi2 epitaxial and doubly-positioned on (111)Si; images indicate that both silicon-silicide interfaces are atomically abrupt, smooth well-characterized. It shown that, although critically dependent film thickness defocus, careful experimental determination these parameters comparison...

Transmission electron microscopy (TEM) and scanning microscope cathodoluminescence (CL) have been used to determine the influence of edge screw dislocations on light emitting properties InxGa1−xN quantum wells. TEM is locate identify nature dislocations. CL same samples spatial variation luminescence. A direct correlation maps with has established, showing that threading act as nonradiative recombination centers an associated minority carrier diffusion length 200 nm. Threading mixed type...

A combination of transmission electron microscopy imaging and diffraction techniques is used to characterize crystal defects in homoepitaxial GaN thin films. The Burgers vectors dislocations established by combining large-angle convergent beam conventional contrast techniques. It shown that with c, a, c+a are present. Evidence presented dislocation segments lying the interfacial plane dissociated on a fine scale. significance observations for understanding growth discussed.

The dependence of the characteristic X-ray production on electron beam orientation is studied using very thin epitaxially grown single crystals. In crystals Ag and Pd thickness ~100 Å L shell yield can change by more than a factor 2 for small changes in near [111] direction. Theoretical analysis results shows that different Bloch waves do not produce X-rays independently but interference effects occur. significance these observations discussed.

A detailed analysis of the structure Cu2ZnSnS4 (CZTS) nanocrystals synthesized by hot-injection in presence oleylamine is provided employing high resolution TEM, selected area electron diffraction (SAED) and convergent beam (CBED). The nanostructures were investigated as-grown after vacuum thermal treatment at 550 °C. As-grown materials consisted polycrystalline particles with an average size 7 ± 3 nm, which grow 53 13 nm annealing step. This allows investigating initial stages quality film...

Off-axis electron holography in a transmission microscope is used to examine the charge on threading edge dislocations n-GaN (0001). It shown that crystal inner potential reduced within 10 nm of dislocation consistent with negatively charged core. The results can be explained by simple unscreened due core about 4 x 10(7) electrons cm (-1). origin this discussed. application method other types also considered.

Abstract The atomic structure of the epitaxial NiSi2-(001)Si interface has been investigated by transmission electron microscopy. Lattice images cross-sections, taken on a JEOL 200 CX microscope with point-to-point resolution 2·4Å, are compared simulated multislice and suggest model which is atomically abrupt silicon atoms everywhere tetrahedrally coordinated. Diffraction contrast analysis (001) specimens used to establish presence interfacial dislocations Burgers vector type α/4〈111〉...

We have investigated normal and resonant Raman scattering in Me-doped ZnO nanorods (Me = Mn, Co, Cu Ni) prepared by thermal diffusion. Experimental results show that the spectra consist of conventional modes associated with wurtzite impurity-related additional modes. Under conditions, only longitudinal optical (LO) phonon its overtones are observed. The number LO lines their relative intensity depend on doping element level. For doped Ni, we observed up to eleventh order. This situation does...

Arrays of dislocation free uniform Ga-polar GaN columns have been realized on patterned SiOx/GaN/sapphire templates by metal organic vapor phase epitaxy using a continuous growth mode. The key parameters and the physical principles three-dimensional are identified, their potential for manipulating process is discussed. High aspect ratio achieved silane during growth, leading to n-type columns. vertical rate increases with increasing flow. In core–shell columnar LED structure, shells...

Correlations between the population of deep trap states in an array TiO2 nanotubes (NT) and dynamic photocurrent responses under supra-band-gap illumination are investigated. Ordered arrays NT 10 μm length, 125 nm inner diameter, 12 wall thickness featuring strong anatase character were obtained by anodization Ti ethylene glycol solution containing NH4F. Cyclic voltammograms at pH show characteristic for nanostructured electrodes, particular a sharp cathodic peak as electron density film...

A new solution based route for depositing Cu2ZnSnS4 (CZTS) thin films is described, focusing on the effects of Sb and Na codoping. X-ray diffraction Raman spectroscopy confirm formation kesterite phase with a measurable improvement in crystallinity upon doping. sharp band gap absorption edge at 1.4 eV determined from diffuse reflectance measurements, while photoluminescence yield sharpening band-to-band emission spectra are observed presence Sb. The performance devices configuration...

Low resistivity (ρ ~ 3–24 mΩ·cm) with tunable n- and p-type single phase Cu2O thin films have been grown by pulsed laser deposition at 25–200 °C varying the background oxygen partial pressure (O2pp). Capacitance data obtained electrochemical impedance spectroscopy was used to determine conductivity (n- or p-type), carrier density, flat band potentials for samples on indium tin oxide (ITO) 25 °C. The Hall mobility (μH) of estimated be ~0.85 cm2/V.s 4.78 respectively quartz substrate An...

Heteroepitaxial growth of β-Ga2O3 on (001) diamond by metal–organic chemical vapor deposition (MOCVD) is reported. A detailed study was performed with Transmission Electron Microscopy (TEM) elucidating the epitaxial relation (−201) β-Ga2O3||(001) and [010]/[−13–2] ||[110]/[1–10] diamond, presence different crystallographically related variants apparent from selected area diffraction patterns. model explaining arrangement atoms along ⟨110⟩ demonstrated a lattice mismatch 1.03–3.66% in...

CdSe1–xTex quantum dot (QD) alloys are characterized by high luminescence yields and a strong band gap bowing as function of the Se:Te ratio, featuring longer emission wavelengths than CdTe or CdSe dots identical size. In this contribution, these properties rationalized examining structure edge energy functions x. The QDs were synthesized employing "hot-injection" method, in presence either trioctylphosphine oxide (TOPO) octadecene (ODE) Cd precursor solvent. Elementary analysis indicated...

As an instrument, the scanning transmission electron microscope is unique in being able to simultaneously explore both local structural and chemical variations materials at atomic scale. This made possible as types of data are acquired serially, originating from sample interactions with a sharply focused probe. Unfortunately, such scanned can be distorted by environmental factors, though recently fast-scanned multi-frame imaging approaches have been shown mitigate these effects. Here, we...

This paper explains how the convergent beam electron diffraction (CBED) and large angle (LACBED) techniques can be used to study crystal defects, bicrystals, multilayers. It is shown LACBED technique in particular derive magnitude sign of Burgers vectors dislocations displacements at stacking faults. For bicrystals multilayers examined plan-view, gives rocking curve for a chosen reflection. enables layer strains measured approximately 0.1% composition profiles derived both periodic aperiodic...

Abstract The structure of the epitaxial Pd2Si/(111)Si interface has been investigated by transmission electron microscopy. Observations normal to using weak-beam technique demonstrate presence misfit dislocations and support a model where atomically smooth regions are coherent associated with interfacial steps. High-resolution lattice images (110) cross-sectional specimens consistent this model, showing characteristic image features which may be explained theoretical multislice simulations....

In the present work, influence of annealing on structure, electron spin resonance (ESR), and Raman scattering (RS) spectra x at. % Mn-doped ZnO (x=4 8) ceramic compounds has been systematically investigated. The samples were annealed at temperatures (Tan) between 400 1000°C for 12h. obtained results revealed strong dependence x-ray diffraction, ESR, RS temperature Tan. Mn2+ ions did not substitute into Zn2+ sites in range 400–600°C but started to Tan>600°C. this investigation provide...

Transmission and scanning electron microscopies are used to examine the epitaxial lateral overgrowth of GaN on nanocolumns grown AlN/(0001)sapphire by molecular beam epitaxy. Initially, N-rich growth gave a bimodal morphology consisting defect-free Ga-polar emanating from compact, highly defective N-polar layer. Under subsequent Ga-rich conditions, grew laterally produce continuous overlayers. Threading dislocation (TD) densities in overlayer were range 108–109cm−2, up two orders magnitude...