A5012882715- Luminescence Properties of Advanced Materials
- Radiation Detection and Scintillator Technologies
- Ga2O3 and related materials
- Advanced Photocatalysis Techniques
- ZnO doping and properties
- Atomic and Subatomic Physics Research
- Semiconductor materials and devices
- Glass properties and applications
- Nuclear Physics and Applications
- Nuclear materials and radiation effects
- GaN-based semiconductor devices and materials
- Silicon Carbide Semiconductor Technologies
Washington State University
2013-2020
University of Utah
2020
University of Idaho
2018
Lawrence Livermore National Laboratory
2017-2018
Magnesium-doped gallium oxide may be utilized as a semi-insulating material for future generations of power devices. Spectroscopy and hybrid functional calculations were used to investigate defect levels in Czochralski-grown β-Ga2O3. Substitutional Mg dopants act deep acceptors, while substitutional Ir impurities are donors. Hydrogen-annealed Ga2O3:Mg shows an IR peak at 3492 cm−1, assigned O-H bond-stretching mode neutral MgH complex. Despite compensation by Si hydrogen passivation, high...
We report polarization dependent photoluminescence studies on unintentionally-, Mg-, and Ca-doped β-Ga2O3 bulk crystals grown by the Czochralski method. In particular, we observe a wavelength shift of highest-energy UV emission which is pump photon energy polarization. For 240 nm (5.17 eV) excitation almost no observed between E||b E||c, while centroid clearly for 266 (4.66 eV), lying band absorption onsets two polarizations. These results are consistent with originating from transitions...
Currently, Fe doping in the ~10^18 cm-3 range is most widely-available method for producing semi-insulating single crystalline beta-Ga2O3 substrates. Red luminescence features have been reported from multiple types of Ga2O3 samples including Fe-doped -Ga2O3, and attributed to or N at O. Herein, however, we demonstrate that high-intensity red commercial substrates consisting two sharp peaks 689 nm 697 superimposed on a broader peak centered 710 originates Cr impurities present concentration...
In this study, LiAlO2 crystals doped with rare-earth elements and Ti were produced by the CZ method spectroscopic neutron detection properties investigated. Photoluminescence revealed no clear luminescent activation of dopants though some interesting luminescence was observed from secondary phases within crystal. Gamma-ray pulse height spectra collected using a 137Cs source exhibited only Compton edge for crystals. Neutron modeling Monte Carlo N-Particle Transport Code most neutrons used in...
In this study, four yttrium aluminum garnet single crystals co-doped with cerium and lithium were produced by the Czochralski method scintillation defect properties investigated. Our results demonstrated an increase in luminescence Li co-doping as well elimination of longer decay times. Surprisingly, although is monovalent, no oxidation from Ce3+ to Ce4+ was found would be expected maintain charge neutrality. Additionally, thermoluminescence indicated a reduction trapping carriers shallow...
Single crystal cerium doped yttrium aluminum garnet boules were grown by the Czochralski method. Cerium concentrations held at 1.0 at. % (with respect to in an on stoichiometric charge) but melt stoichiometry ranged from 10.0 yttria rich alumina 5.0% increments. Photo-luminescence, lifetime, and scintillation data demonstrate a measureable decrease UV defect emission as becomes rich. This is strongly consistent with suppression of equilibrium YAl3+ antisite boule shifts towards does not...
Abstract This work reports on high current density 1.2 kV class HfO 2 -gated vertical GaN trench metal-oxide-semiconductor field-effect transistors (MOSFETs). An output of 330 mA mm −1 is reported at a drain bias five volts, which, to our knowledge, over ten-times the highest values for or SiC MOSFETs. also showcases significant achievement in demonstrating substantially thick (100 nm) with simultaneous low leakage (0.5 nA MV cm ), breakdown strength (5.2 and recorded dielectric constant (22.0).