A5028183545- Acoustic Wave Resonator Technologies
- Gas Sensing Nanomaterials and Sensors
- Analytical Chemistry and Sensors
- GaN-based semiconductor devices and materials
- Advanced Chemical Sensor Technologies
- Ferroelectric and Piezoelectric Materials
- Metal and Thin Film Mechanics
- Advanced MEMS and NEMS Technologies
- Advancements in Solid Oxide Fuel Cells
- Advanced ceramic materials synthesis
- Electronic and Structural Properties of Oxides
- Semiconductor materials and devices
- Boron and Carbon Nanomaterials Research
- Electrochemical Analysis and Applications
- MXene and MAX Phase Materials
- Intermetallics and Advanced Alloy Properties
- X-ray Diffraction in Crystallography
- Nonlinear Optical Materials Research
- Advanced materials and composites
- Ga2O3 and related materials
- Dental materials and restorations
- Smart Materials for Construction
- Corrosion Behavior and Inhibition
- Aluminum Alloys Composites Properties
- Ultrasonics and Acoustic Wave Propagation
National Institute of Advanced Industrial Science and Technology
2017-2024
Kyushu University
2011-2017
The aim of this study is to obtain a systematic insight into the scandium (Sc) concentration dependence spontaneous polarization (Psp) in ScxAl1−xN by using first-principles calculations. From calculated results, we observe that structural change from c-axis polarized wurtzite structure nonpolarized layered hexagonal takes place at x = 0.67, and decreases nonlinearly with Sc concentration. Furthermore, calculate polarizations each cation individually find aluminum–nitrogen (Al–N) (PspAlN)...
The enhancement mechanism of piezoelectric properties by codoping Mg + X (X = Nb, Ti, Zr, Hf) into aluminum nitride (AlN) was investigated first-principles calculations. Theoretically, the constant (d33) can be increased when elastic (C33) is decreased and stress (e33) increased. All components e33, which consists clamped Born effective charge (Z33), strain sensitivity (du/dε) internal parameter, were improved addition AlN. decrease in C33 increase du/dε that observed X-codoped AlN indicate...
In this study, the piezoelectric properties of scandium-alloyed gallium nitride (ScGaN), which is expected to be applied microelectromechanical systems devices, are evaluated by first-principles calculations. The constant (d33) GaN found increase up approximately 30 times upon addition 62.5 mol. % Sc. stress (e33) increases and elastic (C33) decreases with increasing Sc content ScGaN, driving rise d33. improved ScGaN compared those largely attributed softening, thought related transition...
Abstract Polarity is among the critical characteristics that could governs functionality of piezoelectric materials. In this study, polarity aluminum nitride (AlN) thin films was inverted from Al-polar to N-polar by doping Si into AlN in range 1–15 at.%. inversion also occurred when MgSi codoped with Mg ratio less than 1. However, can be reversed and greater The effect addition investigated regards their crystal structure, lattice parameters, distribution oxidation state each elements....
This study employs first-principles calculations to investigate how introducing Yb into aluminum nitride (AlN) leads a large enhancement in the material’s piezoelectric response (d33). The maximum d33 is calculated be over 100 pC/N, which 20 times higher than that of AlN. One reason for such significant improvement elastic-softening effect, indicated by decrease elastic constant, C33. strain sensitivity (du/dε) internal parameter, u, also an important factor improving stress e33. On basis...
Abstract In this study, Sc concentration dependence of x Al 1− N/AlN/poly-crystalline diamond/Si surface acoustic wave (SAW) characteristics at high from 23.8% to 44.3% was investigated by fabricating one-port SAW resonator frequency. 3.8 GHz fabricated on 0.43 0.57 N showed an excellent performance electro-mechanical coupling coefficient ( K 2 ) as 6.34% for 2nd mode Sezawa wave, which enables a wide bandwidth in frequency applications. The temperature approximately −40 −50 ppm deg −1 the...
A significant enhancement in the hydrogen (H2) sensitivity as well selectivity after aging for more than 40 days has been observed a mixed-potential-type sensor using ZnO (+84 wt % Ta2O5) sensing electrode (SE) and yttria-stabilized zirconia (YSZ) solid electrolyte. The effect of process enhancing characteristics Ta2O5)-SE was studied here by investigating changes morphology, crystal structure, chemical surface state, catalytic properties SE material before at 500 °C 80 days. X-ray...