A rich variety of optical centers with high energy local vibrational modes has been found in electron-irradiated 4H-SiC in both the as-irradiated and annealed states. These energies have been measured and the annealing dependence of the optical centers has been investigated by low-temperature... (Read more)

This paper deals with the positive identification by low-temperature photoluminescence microspectroscopy of the two spin states of the dicarbon antisites in 4H-SiC. The defects are created by high-dose electron irradiation at room temperature or by subsequent exposure to intense 325 nm radiation at... (Read more)

The distribution of deep traps in a bulk dielectric (Al₂O₃) is imaged by low vacuum scanning electron microscopy (LVSEM). The image contrast corresponds to spatial variations in radiation-induced, field-enhanced conductivity. A methodology is presented for identification of... (Read more)

In this paper we describe the use of electron backscatter diffraction (EBSD) mapping and electron channeling contrast imaging—in the scanning electron microscope—to study tilt, atomic steps and dislocations in epitaxial GaN thin films. We show results from a series of GaN thin films of... (Read more)

The authors present space-resolved spectroscopic data on organic layers of a degraded organic light-emitting device. The data were obtained using a scanning photoelectron microscope (SPEM) coupled with peel-off technique to directly probe the uncontaminated organic layers, which were covered with... (Read more)

Only a few years ago, an account of degradation of silicon carbide high-voltage p-i-n diodes was presented at the European Conference on Silicon Carbide and Related Compounds (Kloster Banz, Germany, 2000). This report was followed by the intense effort of multiple groups... (Read more)

ZnO substrate crystals from two different sources, and epitaxial layers have been studied by SEM, AFM, photoluminescence and EPR. Although fabricated by the same growth principle, i.e. the hydrothermal technique, the substrates differ in terms of purity and structural quality. In the PL spectra of... (Read more)

The structural, optical and magnetic properties of nanostructured ZnO films co-doped with cobalt and aluminium have been studied. The nanocrystalline films, with cluster sizes in range 50–100 nm, were deposited by pulsed laser ablation in a mixed atmosphere of oxygen and helium. The... (Read more)

We prepared ZnO nanostructures using chemical and thermal evaporation methods. The properties of the fabricated nanostructures were studied using scanning electron microscopy, x-ray diffraction, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy. It was found that the... (Read more)

The properties of ZnO tetrapod and multipod structures were investigated using scanning electron microscopy, x-ray diffraction, photoluminescence (PL), and electron paramagnetic resonance (EPR) spectroscopy. While there is relationship between g = 1.96 EPR and green PL in some of the samples,... (Read more)

We have observed the nagnetic resonance of conduction electrons in n-type indium antimonide, by the "heating" of the electron kinetic-energy temperature via the slsctron spins. This is the first direct evidence suggesting a contribution of spin-orbit coupling to relaxation in this system. In a steady-state spin-resonance experiment, a power P_S=(M₀=M_Z)H/T₁ is transferred to the systems(reservoirs) towards which the spins relax. Here, M₀ is the equilibrium magnetization, M_Z the component of the magnetization along the magnetic field H, and T1 the relaxation time. The reservoir of interest in our case is the kinetic energy of the eledtrons, and this is detected by an increase in the mobility μ. To our knowledge. this is the first observation of the power flow, due to relaxation, from the spins to a reservoir,applied to the ditection of magnetic resonance of conduction-electron spins. It differs in principle from usual spin-resonance observation methods, which are based on electromagnetic interactions of the spin system, such as the voltage induced in a resonator by the rotating magnetic moment, or again such as power absorption P_S=M_yH_x from the rotating field H_x by the out-of- phase component M_y.Besides providing information on the relaxation mechanism, the present method (that we call "ralaxation" method) should also in some cases by much more sensitive than the usual "electromagnetic" detection methods. (Read more)

Aerosol-assisted vapor phase synthesis aimed at preparation of magnetic semiconductor nanopowders of Ga1−xMnxN is carried out both from aqueous and methanol solution mixtures of gallium nitrate and manganese (II) nitrate. After an additional pyrolysis at 1000 °C under an ammonia flow,... (Read more)

Freeze-drying, as a cryochemical powder processing method is applied in the synthesis of ZnO submicrometer to nanosized powders. The process involves rapid freezing of the sprayed precursor solution, drying under vacuum by sublimation of the solvent and salt decomposition to oxide by thermal... (Read more)

Tungsten phosphate glasses mixed with the three different modifier oxides, viz. PbO, ZnO and CaO doped with Er2O3 were prepared. The glasses were characterised by X-ray diffraction spectra, electron microscopy and differential thermal analysis. Optical absorption and photoluminescence spectra of... (Read more)

The ramification of micropipes is observed using scanning electron microscopy, optical microscopy, and synchrotron x-ray radiography. The conditions for the ramification of dislocated micropipes are determined theoretically within a model when the angles between dislocation lines are small. It is... (Read more)

Hexagonal voids observed in sublimation grown SiC boules were examined using optical microscopy, atomic force microscopy (AFM), scanning electron microscopy, KOH etching, and synchrotron white-beam x-ray topography. Voids formed at imperfections in the attachment layer between the seed and crucible... (Read more)

GaN community has recently recognized that it is imperative that the extended, and point defects in GaN and related materials, and the mechanisms for their formation are understood. This is a first and an important step, which must be followed by defect reduction before full implementation of this... (Read more)

Experimental studies of size-related effects in silicon nanocrystals are reported. We present investigations carried out on nanocrystals prepared from single-crystal Si:P wafer by ball milling. The average final grain dimension varied depending on the way of preparation in the range between 70 and... (Read more)

The sublimation epitaxy growth process has been studied. The structural quality of the grown layers improves compared with the substrate mainly due to a diminished domain structure misorientation. Optical microscopy shows that the as-grown surfaces are free of typical defects appearing in silicon... (Read more)

We explore the interrelationships between the green 510 nm emission, the free-carrier concentration, and the paramagnetic oxygen-vacancy density in commercial ZnO phosphors by combining photoluminescence, optical-absorption, and electron-paramagnetic-resonance spectroscopies. We find that the green... (Read more)

Investigations have been made on the effects of pulse laser annealing on the ceramics (Zn,Mn)O by means of electron spin resonance (ESR) measurements. A remarkable change in the ESR spectrum was observed after annealing by a Nd:YAG pulse laser (=1.064 µm, 5–7 J/cm²). It... (Read more)

The velocity v of dislocation half-loops introduced into swirl-free floating-zone grown undoped silicon has been measured at 420°C in the resolved shear stress range 30 <τ<300 MPa. Clearly impurity atoms interact with dislocations in this material. Using the starting value of v we found the two types of 60° dislocations, which are distinguished by the sequence of their partials, to have different velocities. Furtheron the velocity depends not only on τ, but also on the elastic strain of the lattice. In the second part the papers review EPR spectroscopy of plastically deformed silicon and collects new results on the activity of dislocations in this material as trapping / recombination centers (decay of photo-EPR, photoluminescence, EBIC microscopy and photoplastic effect). (Read more)