Hideo Isshiki

Highly erbium-doped zinc–oxide thin film prepared by laser ablation and its 1.54 μm emission dynamics

Erbium-doped ZnO (ZnO:Er) thin films were fabricated by the KrF excimer laser ablation technique, which is a useful and simple technique to dope Er atoms on the order of 1020 cm−3 into a host material. As-prepared ZnO:Er films showing strong c-axis orientation with a hexagonal crystalline structure indicate a low electrical resistivity of 6.4×10−3 Ω cm. The sharp and intense photoluminescence (PL) at 1.54 μm originating from the intra-4f transition in the Er3+ ions as well as PL in UV region from the ZnO host were observed even at room temperature. Significant distinction arising from the different Er emission centers responsible for the 1.54 μm emission cannot be found in the temperature dependence between the ZnO:Er and Si:Er film as a reference, except for the PL spectrum feature and main PL peak position. This result suggests the existence of Er emission centers in ZnO:Er and Si:Er films that are different from each other. The details of Er-related 1.54 μm emission dynamics of ZnO:Er films have been i...

Self-assembled infrared-luminescent Er–Si–O crystallites on silicon

Optically active and electrically excitable erbium complexes on silicon are made by wet-chemical synthesis. The single-crystalline Er–Si–O compound is formed by coating a Si(100) substrate with an ErCl3∕ethanol solution, followed by rapid thermal oxidation and annealing. Room-temperature Er-related 1.53μm photoluminescence is observed with a peak linewidth as small as 4meV. The complexes can be excited directly into the Er intra-4f states, or indirectly, through photocarriers. Er concentrations as high as 14at.% are achieved, incorporated in a crystalline lattice with a 0.9nm periodicity. Thermal quenching at room temperature is only a factor 5, and the lifetime at 1.535μm is 200μs.

1.54 μm emission dynamics of erbium-doped zinc-oxide thin films

Erbium-related 1.54 μm emission dynamics of Er-doped ZnO thin films has been investigated for the different excitation conditions. The excitation was achieved either by exciting indirectly Er3+ ions due to an electron–hole-mediated process or exciting directly discrete energy levels of Er3+ ions. There is no change in the 1.54 μm emission spectrum feature in spite of the different excitation conditions, whereas dramatic change can be seen in the rise time of 1.54 μm emission. The shorter rise time of 1.54 μm emission observed for indirect excitation implies an excitation efficiency superior to direct excitation of Er3+ ions.

Fabrication and stimulated emission of Er-doped nanocrystalline Si waveguides formed on Si substrates by laser ablation

Er-doped nanocrystalline Si (nc-Si) waveguides were fabricated on Si substrates and investigated by optical pumping. A stimulated emission at 1540 nm was demonstrated at room temperature. The sizes of the fabricated Er-doped nc-Si waveguides were 5000 nm×200 nm×L, where L is the cavity length and is changed from 1 to 10 mm. Superlinear optical outputs at 1540 nm were observed for the waveguides longer than 3 mm. The threshold of the optical output where the stimulated emission occurs is in the order of 10 MW/cm2, and is demonstrated to depend on the cavity length of the waveguides. A large reduction of decay lifetimes of the light output from a cleavage facet of the Er-doped nc-Si waveguides was observed when the pumping power density exceeded the thresholds indicating an increase of transition probabilities in intra-4f electrons in Er3+ ions caused by the stimulated emission. Better 1540 nm laser performance and lower pumping power density should be obtained by optimizing the device structure and increas...

Electronic structures of B 2p and C 2p levels in boron-doped diamond films studied using soft x-ray absorption and emission spectroscopy

X-ray absorption (XAS) and emission (XES) spectroscopy near B K and C K edges have been performed on metallic (

Time response of 1.54 μm emission from highly Er-doped nanocrystalline Si thin films prepared by laser ablation

\ensuremath{\sim}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{at.}\phantom{\rule{0.2em}{0ex}}%

Impact excitation of the erbium‐related 1.54 μm luminescence peak in erbium‐doped InP

B, B-diamond) and semiconducting (

Fabrication and characterization of Er silicates on SiO2/Si substrates

\ensuremath{\sim}0.03\phantom{\rule{0.3em}{0ex}}\mathrm{at.}\phantom{\rule{0.2em}{0ex}}%

Room‐temperature luminescence from erbium‐doped silicon thin films prepared by laser ablation

B and N, BN-diamond) doped diamond films. Both B K XAS and XES spectra show a metallic partial density of states (PDOS) with the Fermi energy of

Photoluminescence enhancement and high gain amplification of ErxY2−xSiO5 waveguide

185.3\phantom{\rule{0.3em}{0ex}}\mathrm{eV}