A5021072095- Chalcogenide Semiconductor Thin Films
- Semiconductor Quantum Structures and Devices
- Solid-state spectroscopy and crystallography
- Thermography and Photoacoustic Techniques
- Quantum Dots Synthesis And Properties
- Semiconductor materials and interfaces
- Advanced Semiconductor Detectors and Materials
- Silicon and Solar Cell Technologies
- GaN-based semiconductor devices and materials
- Phase-change materials and chalcogenides
- Crystal Structures and Properties
- Nanowire Synthesis and Applications
- Semiconductor materials and devices
- solar cell performance optimization
- Photoacoustic and Ultrasonic Imaging
- Thin-Film Transistor Technologies
- Copper-based nanomaterials and applications
- Ga2O3 and related materials
- Glass properties and applications
- ZnO doping and properties
- Advanced Thermoelectric Materials and Devices
- Calibration and Measurement Techniques
- Gas Sensing Nanomaterials and Sensors
- Machine Learning in Materials Science
- Luminescence Properties of Advanced Materials
University of Miyazaki
2014-2024
Japan Society for the Promotion of Science
2022
The University of Tokyo
2020
National College of Technology, Wakayama College
2012
Ehime University
2000
University of Toronto
1999
University of New Brunswick
1999
Kurume University
1968-1988
Université de Sherbrooke
1983
Kyushu University
1975-1978
Abstract To reduce fluctuations in the performance of lattice-mismatched solar cells within a wafer, it is necessary to characterize and quantify effect misfit dislocations, caused by strain relaxation, on cell. this end, relationship between preferential glide planes (GPs) carrier generation-recombination process InGaAs with low (LowV) high (HighV) open-circuit voltages has been investigated study. The GPs β dislocations HighV were uniformly controlled wafer plane. However, LowV contained...
Abstract The laser heterodyne photothermal displacement (LH-PD) method, a recently developed technique, enables measurement of absolute surface displacements, which are otherwise challenging to measure with other methods. This method offers significant potential for quantifying physical properties that difficult achieve traditional In this study, we aimed estimate the thermal diffusivity and carrier lifetime Si using machine learning model based on time variation obtained LH-PD method. By...
Temperature-dependent photoluminescence measurements were carried out between 8 and 300 K on CuInS2 single crystals grown by a traveling heater method. Ten distinct peaks present in the near-band edge region. Four unknown peaks, observed at K, found to be due bound exciton emission. Moreover, luminescence remained stable up room temperature.
GaSe(Cu)/InSe heterojunctions have been formed by bringing the cleavage surface of undoped n-InSe and Cu-doped p-GaSe into direct contact. Transport phototransport properties are studied measurements capacitance–voltage, current–voltage, spectral response short-circuit current. Moreover, efficiency parameters under illumination estimated using open-circuit voltage These characteristics compared with those GaSe(Un)/InSe fabricated n-InSe. The series resistance is found, value which about 103...
Abstract A polytype of InSe single crystals is determined to be γ‐type by means X‐ray Laue and diffractometer measurements. Polarized Raman scattering studies are carried out at room temperature the spectra analysed using normal modes γ‐InSe. Two lines 1 mode (118, 228 cm −1 ) two E (43, 180 observed. An additional line 214 attributed an LO phonon with symmetry.
Measurements of photoconductivity and photo-Hall effect have been made on Zn-doped p-type InSe in the temperature range from 220 to 330 K. The results are interpreted by a two-carrier model under illumination assuming that Δ n = p , where photogenerated carrier concentration electrons holes, respectively. obtained mobility ratio b is determined as 9.5×10 -2 T 0.7 dependence hole can be well fitted developed Schmid (Nuovo Cimento B21 (1974) 258).
Zinc (Zn) is doped into GaSe single crystals grown by the Bridgman technique in a wide range from 0.005 to 0.5 at. % stoichiometric melt. Radiative recombination mechanisms have been investigated using photoluminescence (PL) measurements. The PL spectra Zn-doped samples at 77 K are dominated three emission bands 1.75, 1.63, and 1.27 eV. 1.63 eV enhanced with increase amount of Zn. In addition results Hall effect measurements, it found that associated acceptor levels 0.12 0.3 above valence...
Room-temperature photoacoustic (PA) spectra of p-type silicon single crystals were measured by using a piezoelectric transducer as detector. Two peaks at 1.08 and 1.20 eV observed. Since the peak appears only in boron-doped samples, we consider this to be due boron impurity level. The beyond band gap observed for both p- n-type samples is considered an apparent one bending sample highly absorbing region. effect modulation frequency detector geometries are explained well taking into account...
The photoacoustic (PA) spectra of layer halide ${\mathrm{BiI}}_{3}$ has been studied by a piezoelectric transducer as detector in the temperature region from 115 K to room temperature. Four peaks G (1.97 eV), A (2.03 B (2.17 and C (2.38 eV) are observed PA at K. Peaks explained transition ground first excited states direct exciton. onset transitions spin-orbit split valence band occurs peak C. decrease signal which begins is interpreted generation different pathways for relaxation carriers....
N-type ZnO thin films were successfully grown by sol-gel dipping coat method on glass substrates at 300–600 °C under air atmosphere. Poly obtained more than 300 °C. Values of full width half maximum (0002) peak the XRD spectra became small with increasing substrate temperatures. Optical transmittances increased The optical transmittance Ga-doped was larger In- and Al-doped (5 wt%). Moreover, a resistivity smaller those films. X-ray photoemission spectroscopy (XPS) results indicated that...
The optical properties of ZnO nanorods and nanowires grown by our newly developed nanoparticle-assisted pulsed-laser deposition (NAPLD) technique were studied photoluminescence (PL) spectroscopy. This NAPLD technique, which does not require a catalyst for crystal growth, is expected to synthesize high-quality nanostructured crystals. green luminescence (GL) band ultraviolet (UVL) observed at low temperature investigated these UVL consists several sharp emission lines due free excitons,...
A general theoretical model for the infrared photothermal radiometric (PTR) signal from a semiconductor wafer is developed case of three-dimensional sample geometry with finite thickness. Carrier diffusion and heat conduction along radial direction as well thickness coordinate are taken into account. The simulated results modulation frequency dependence PTR amplitude phase applied to experimental data Si wafers. Good agreement between curves obtained several electronic thermophysical...
Time evolution of $\mathrm{EL}2$ thermal recovery has been investigated in detail by a piezoelectric photothermal method. Results showed simple saturating behavior for $T>120\mathrm{K}$ and sigmoid-function-like $T<120\mathrm{K},$ which were both quantitatively analyzed with an autocatalytic-reaction rate equation. The latter mode indicates correlation between defects, promotion charge transfers from recovered to unrecovered defects can be suggested. A three-center-complex model...
Impurity levels in Cd-doped GaSe have been studied by using photoluminescence (PL) measurements. The PL spectra at 77 K are dominated three new emission bands 1.95, 1.75, and 1.62 eV. intensity the peak energy of 1.95 eV measured as a function temperature. It is shown that band due to transition between conduction acceptor level 0.18 above valence band. caused from donor 0.37 below 0.13 increases with increasing Cd concentration.