Electron paramagnetic resonance (EPR) and electron-nuclear double (ENDOR) are used to identify characterize electrons trapped by oxygen vacancies holes lithium in tetraborate (Li2B4O7) crystals. Our study includes a crystal with the natural abundances of B10 B11 highly enriched B10. The as-grown crystals contain isolated vacancies, copper impurities, all nonparamagnetic charge states. During an irradiation at 77 K 60 kV x-rays, doubly ionized trap while singly monovalent impurities holes....

Electron paramagnetic resonance (EPR), electron-nuclear double (ENDOR), and thermoluminescence (TL) are used to characterize the primary electron hole trapping centers in a lithium tetraborate (Li2B4O7) crystal doped with Ag. Three defects, two holelike one electronlike, observed after exposure at room temperature 60 kV x-rays. The as-grown contains both interstitial Ag+ ions substituting for Li+ ions. During irradiation, substitutional (4d10) trap holes distinct Ag2+ (4d9) formed. These EPR...

Gd(2)O(3) and Gd-doped HfO(2) films were deposited on p-type silicon substrates in a reducing atmosphere. Gd 4f photoexcitation peaks at roughly 7 5 eV below the valence band maximum have been identified using resonant photoemission of films, respectively. In case Gd(2)O(3), strong hybridization with O 2p is demonstrated, there evidence that weighted exhibits dispersion bulk structure. The rectifying (diode-like) properties HfO(2)-silicon Gd(2)O(3)-silicon heterojunctions are demonstrated.

The four dopants (Nd, Gd, Dy, and Er) substitutionally occupy the Li+ sites in lithium tetraborate (Li2B4O7: RE) glasses as determined by analysis of extended X-ray absorption fine structure. are coordinated 6-8 oxygen at a distance 2.3 to 2.5 Å, depending on rare earth. inverse relationship between RE¬ O coordination earth (RE) atomic number is consistent with expected lanthanide radial contraction increased number. Through near edge structure, adopt RE3+ valence state. There indications...

The placement of the Gd, Er and Yb 4f states within GaN valence band has been explored by both experiment theory. 4d–4f photoemission resonances for various rare-earth(RE)-doped thin films (RE = Er, Yb) provide an accurate depiction occupied state GaN. resonant show that major Gd RE weight is at about 5–6 eV below maximum, similar to weights in many other RE-doped semiconductors. For Yb, there a very little enhancement Yb-doped GaN, consistent with large 4f14-δ occupancy. levels qualitative...

Abstract Single crystals of thorium dioxide ThO 2 , grown by the hydrothermal growth technique, have been investigated ultraviolet photoemission spectroscopy (UPS), inverse (IPES), and L 3 M 4 5 X‐ray absorption near edge (XANES). The experimental band gap for large single has determined to be 6 eV 7 eV, from UPS IPES, in line with expectations. combined place Fermi level conduction minimum, making these n‐type, extensive tailing, suggesting an optical region 4.8 excitations occupied...

Abstract The local structure of Mn‐doped Li 2 B 4 O 7 (001) was investigated using extended X‐ray absorption fine (EXAFS) at the Mn K edge and electron paramagnetic resonance (EPR). location dopant in a lithium tetraborate crystal is consistent with occupation site strong oxygen coordination. MnO bond lengths are similar to those observed doping icosahedral based boron carbide where substitutional one cage sites. From EXAFS, manganese does not appear greatly alter overall tetragonal form...

The photoelectric work function of nearly stoichiometric (111) and (100) hydrothermally grown UO 2 was measured to be 6.28 ± 0.36 eV 5.80 eV, respectively. Candidate metals for electrical contacts are identified both rectifying non‐rectifying based on function, lattice compatibility, conductivity.

AlGaN/GaN HFET's were cooled to ~85 K and irradiated a fluence of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> n/cm xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (1 MeV equivalent) gate currents measured. The observed increased leakage current was studied by curve-fitting 4-parameter thermionic trap assisted tunneling model the experimental measurements. parameters constrained least-squares fitting routine applied best fit...

The Schottky barriers formed at the interface between gold and various rare earth doped GaN thin films (RE = Yb, Er, Gd) were investigated in situ using synchrotron photoemission spectroscopy. resultant barrier heights measured as 1.68 ± 0.1 eV (Yb:GaN), 1.64 (Er:GaN), 1.33 (Gd:GaN). We find compelling evidence that layers of do not wet uniformly cover surface, even with doping GaN. Furthermore, trend follows metal work function.

Band-to-band transition energy parameters for single-crystal actinide samples of uranium oxide and thorium were determined compared using spectroscopic ellipsometry critical-point dielectric function analyses. Spectroscopic measurements from the near-infrared to vacuum ultraviolet spectral region used determine functions oxide. The structure is similar between UO2 ThO2 but strongly blue shifted ThO2. We find bandgap energies 2.1 eV 5.4 ThO2, respectively.

The effects of low energy (0.45 MeV) electron radiation on the gate and drain currents Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.27</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.73</sub> N/GaN HFETs are investigated using IV CV measurements. Following irradiation, increase at temperatures reach a saturation level. leakage do not fully account for current increase. room temperature anneal, return to pre-irradiation levels....

Low temperature neutron irradiated Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.27</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.73</sub> N/GaN heterostructures reveal a complex dependent displacement damage formation process. This process results in differences drain currents at low (80 K) versus high (294 temperatures. Irradiation increases the gate and 80 K, decreases current room temperature. These effects saturate ~ 3 times...

Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.27</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.73</sub> N/GaN HFETs were electron irradiated at ~ 80 K. The gate leakage and transistor current measured compared to theoretical tunneling models. results are consistent with previous work but explicitly show that radiation produces point defects in the AlGaN positively charged low temperature.

Integrated circuits are inherently complicated and made more by increasing transistor quantity density. This trend potentially enhances concomitant effects of high-energy ionizing radiation local or impressed electromagnetic interference (EMI). The reduced margin for signal error may counter any gain in hardness from smaller device dimensions. Isolated EMI studies on have been extensively conducted over the past 30 years. However, little focus has placed combined effects. To investigate...

<?Pub Dtl=""?> Carbon nanotube field-effect transistors with <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${\rm Al}_{2}{\rm O}_{3}$</tex></formula> gate dielectrics have been characterized before and after 1 MeV electron irradiation. Pre-irradiation interface trap densities determined by charge pumping measurements were on the order of xmlns:xlink="http://www.w3.org/1999/xlink"><tex...

Electrical properties of defects induced in n-type molecular-beam-epitaxial-grown Al0.14Ga0.86N are studied using deep-level transient spectroscopy (DLTS) to explore the radiation tolerance AlGaN-based electronic and optoelectronic devices. It has been found that four electron traps labeled R1(0.15±0.02eV), R2(0.21±0.02eV), R3(0.26±0.02eV), R4(0.33±0.03eV) created irradiated Al0.14Ga0.86N. The trap R4 is most prominent radiation-induced defect DLTS spectrum appears be unique AlGaN. Although...

The band structure of Li2B4O7(100) and Li2B4O7(110) was experimentally determined using a combination angle-resolved photoemission inverse spectroscopies. experimental gap depends on crystallographic direction but exceeds 8.8 eV, while the bulk is believed to be in vicinity 9.8 qualitative agreement with expectations. occupied indicates relatively large values for hole mass; mass as significantly larger than that electron derived from unoccupied structure. surface characterized by very light...

Highly doped or alloyed Gd 2 O 3 in HfO films form heterojunction diodes with silicon. Single neutron capture events can be identified a Hf 0.85 0.15 1.93 to n-type silicon heterojunction. With long pulse integration times and suppression of the smaller pulses, there is agreement between key height spectral features those predicted by Monte Carlo simulations. The latter align very well decay channels following capture, particularly involving K-shell Auger electron resonances.

Charge pumping and drain current-gate voltage ( I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> - V xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> ) measurements are used to investigate degradation environmental effects in X-ray proton-irradiated graphene transistors. irradiation initially degrades mobility due hole trapping the oxide, induces oxygen-related p-type doping that is evident increase ID once trapped holes anneal out;...

Single crystals of ThO 2 , UO and their solid solutions, U x Th 1– O have been obtained through various hydrothermal growth conditions. This technique offers the better two other processes: (i) single crystal purity as by photochemical nanocrystals; (ii) large/bulk sizes arc melt method. The band gap solution, along with luminescence transition, characterized. occupied unoccupied structures are determined using ultraviolet inverse photoemission spectroscopy electronic was measured to be 3–4...