A5090220092- ZnO doping and properties
- Strong Light-Matter Interactions
- Semiconductor Quantum Structures and Devices
- Perovskite Materials and Applications
- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Plasmonic and Surface Plasmon Research
- Gas Sensing Nanomaterials and Sensors
- Quantum Dots Synthesis And Properties
- Copper-based nanomaterials and applications
- Photonic Crystals and Applications
- Spectroscopy and Laser Applications
- Acoustic Wave Resonator Technologies
- Quantum and electron transport phenomena
- Electronic and Structural Properties of Oxides
- Biotin and Related Studies
- Semiconductor materials and devices
- Nanowire Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
- Chalcogenide Semiconductor Thin Films
Osaka University
2010-2015
Osaka City University
2006-2009
The dynamics of photoluminescence due to biexcitons and exciton-exciton scattering ($M$ $P$ emissions, respectively) has been investigated in the layered-type semiconductor PbI${}_{2}$ by using optical Kerr gate method. We simultaneously observed $M$ emissions under high-density excitation. emission emerges instantaneously, whereas shows a delayed onset whose latency increases as excitation photon energy increases. indicates that takes place after relaxation excitons with excess toward...
The authors have found the self-assembled formation of ZnO hexagonal micropyramids after growth a sufficiently thick layer on (0001) Al2O3 substrate by rf-magnetron sputtering deposition. It was confirmed scanning electron microscopy that orientations are well arranged. reflection and photoluminescence spectra at 10K demonstrate optical properties total high quality. noticeable discovery with use cathodoluminescence spectroscopy is luminescence intensity 30 times stronger than underlying...
Abstract We have investigated the photoluminescence (PL) dynamics of a ZnO thin film under intense excitation conditions at 10 K. In film, PL band due to exciton‐exciton scattering, so‐called P emission, appears. The optical‐Kerr‐gating method with ultrashort gating time 0.6 ps enabled us obtain precise information temporal profiles including peak energy, bandwidth and intensity various detection energies. found that decay emission gradually shortens decreasing energy. change in can be...
We have prepared SiO2/CuCl layered structures and investigated the structural optical properties, focusing on observation of biexciton-resonant hyper-parametric scattering that is a promising process to generate entangled photons. A crystalline CuCl film, which active layer, was grown an Al2O3 substrate by vacuum deposition method, then amorphous SiO2 film as passivation layer for hygroscopic rf-magnetron sputtering method. X-ray diffraction patterns spectra excitons indicate growth...
When an exciton in semiconductor is scattered and its energy decreased far below the resonance of bare state, it has been considered that exciton-polariton created immediately by scattering process, because there no level at energy. However, according to recent time-resolved measurements P emission originating from inelastic exciton-exciton scattering, looks rather natural consider a finite time scale which restricted coherence volume after scattering. In this interpretation, remains as...
Abstract We have investigated the ultrafast dynamics of biexciton photoluminescence (PL) in a 500‐nm thick CuCl thin film at 10 K using an optical Kerr gating method with time resolution ∼1 ps. The was grown by vacuum deposition. It is found that biexciton‐PL intensity has excitation‐power dependent rise time, which reflects formation process biexcitons, while its decay independent excitation power: 6.0 ps dominated transit exciton polaritons travelling through film. Furthermore, from...
We demonstrate that Franz-Keldysh oscillations (FKOs) observed by photoreflectance (PR) spectroscopy are highly sensitive to the surface morphology of AlxGa1−xN layers in AlxGa1−x N heterostructures. Three Al0.2Ga0.8N/GaN heterostructures with different surface-morphology profiles, which confirmed atomic force microscopy, have been investigated. The X-ray-diffraction patterns hardly affected Al0.2Ga0.8N/GaN-layer morphology. In contrast, it is revealed cracks and pits dominating remarkably...
We report on the first observation of thickness-dependent photoluminescence-decay time exciton-exciton scattering in ZnO thin films, which indicates slower propagation photon-like polaritons compared to that bulk by two orders magnitude.
We have investigated the photoluminescence (PL) dynamics of a GaN thin film under intense excitation conditions using an optical-Kerr-gating method. It has been found that PL originating from exciton-exciton scattering (P emission) appears at temperatures lower than around 100 K, while higher P emission vanishes and exciton-electron (H dominates. The ultrashort gating time 0.6 ps enabled us to obtain precise information temporal profiles peak energy, bandwidth, intensity H emission. decay is...
Abstract We have investigated optical properties of ZnO homoepitaxial thin films grown by an rf‐magnetron sputtering method. The surface morphology observed atomic force microscope shows that the roughness is within 1.5 nm. In reflection spectrum at 10 K, fine structures excitonic transitions A and B excitons are observed. photoluminescence (PL) spectrum, free exciton band in addition to very sharp bound‐exciton bands, while defect‐related negligibly weak, reflecting high crystallinity film....