A5067836511- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Acoustic Wave Resonator Technologies
- Photocathodes and Microchannel Plates
- Metal and Thin Film Mechanics
- Semiconductor Quantum Structures and Devices
- Advanced Antenna and Metasurface Technologies
- Microwave Engineering and Waveguides
- ZnO doping and properties
- Electron and X-Ray Spectroscopy Techniques
- Agriculture, Soil, Plant Science
- Thermal Radiation and Cooling Technologies
- Optical Coatings and Gratings
Mie University
2024-2025
Kyoto University
2018-2023
We have fabricated a four-layer polarity-inverted aluminum nitride (AlN) structure using combination of sputtering and face-to-face annealing. investigated the impurity concentrations polarity inversion-domain boundaries (IDBs) AlN structure. Atomic-scale observations revealed that interface IDBs from Al-polar to N-polar consists three monolayers (MLs) O-Al-O, while consist 8–10 ML AlxOyNz. Additionally, positions shifted by 20–30 nm sputtered toward surface, whereas those remained at same...
Deep ultraviolet (UV) emission from AlxGa1−xN-based light-emitting diodes (LEDs) fabricated on semipolar () (r-plane) AlN substrates is presented. The growth conditions are optimized. A high NH3 flow rate during metalorganic vapor phase epitaxy yields atomically flat AlyGa1−yN (y > x) which AlxGa1−xN/AlyGa1−yN multiple quantum wells with abrupt interfaces and good periodicity fabricated. r-AlxGa1−xN-based LED emits at 270 nm, in the germicidal wavelength range. Additionally, line width...
Abstract Reducing the average Al composition of x Ga 1− N/Al y N multiple quantum wells (MQWs) is an effective approach to increase current injection efficiencies far-UV-C LEDs (far-UVC LEDs). A reduction can be realized by decreasing Al-composition differentiation between well and barrier layers. Compared conventional MQWs, a 230 nm wavelength far-UVC LED equipped with single-Al-composition 39 thick light-emitting layer exhibits higher external efficiency (EQE). The EQE low (∼1%) enhanced...
Face-to-face annealed and sputter-deposited aluminum nitride (FFA Sp-AlN) has potential in deep-ultraviolet light-emitting devices. Herein, the effects of substrate off-cut angle (θsub) from an r-plane sapphire toward c-axis projection direction sputtering temperature (Tsp) on crystallinity surface morphology a-plane AlN films are investigated. Increasing θsub minus-off direction, which occurs when approaches c-plane, lowering Tsp suppress mixing anomalous non-a-direction oriented domains....
We investigate the internal quantum efficiencies (IQEs) of AlGaN/AlN wells (QWs) on (0001) c- and semipolar (11¯02) r-planes in far-ultraviolet C (far-UVC) region using time-integrated photoluminescence time-resolved PL spectroscopies. Stronger emissions from r-QWs are observed, especially at shorter wavelengths, indicating that exhibit higher IQEs than c-QWs. Analyses experimental results suggest main reason for far-UVC is radiative lifetimes an increase a slow decay component, which might...
Semipolar AlxGaN films (∼660 nm thick) are fabricated on (102) (r-plane) AlN substrates. X-ray diffraction measurements suggest that the structural quality is relatively good although lattice relaxation occurs. The experimentally evaluated degrees 0.90 and 0.72 along [10] [110] directions, respectively. These values, which much larger than those of c-plane for a similar Al composition thickness, reproduced by calculation. Dislocations due to confined vicinity AlxGaN/AlN interface, suggesting...