Papers by kuniko takemoto
Extended Abstracts of the 1991 International Conference on Solid State Devices and Materials, 1991
Microstructure and lattice expansion of porous sil-icon (PS) layers, formed on p-type silicon waf... more Microstructure and lattice expansion of porous sil-icon (PS) layers, formed on p-type silicon wafers (0.02flcm) rmder various current densities, have been investigated by means of scanning electron microscopy, cross-sectional trans- mission electron microscopy and gas adsorption technique, and precise X-ray diffractometry. The pore morphology and lattice distortion of PS layers was dependent on pore size. Small-pores showed more complicated morphology than large ones. When PS I-ayers \rere produced at high current densities, remaining silicon parts shornred large lattice distortions. The lattice distortion is ascribed to diffused hydrogen atoms into silicon matrix and repulsion force due to chemisorbed hydrogen atoms near pore surfaces.
Japanese Journal of Applied Physics, 1996
Cathodoluminescence (CL) from n-type porous silicon (PS) was studied using a transmission electro... more Cathodoluminescence (CL) from n-type porous silicon (PS) was studied using a transmission electron microscope (TEM) equipped with the CL detection system. Two luminescence peaks at wavelengths of 660 nm and 420 nm were observed from a cross-sectional sample. The monochromatic CL images clearly reveal the spatial distribution of these luminescences along the depth direction; the 660 nm luminescence is mainly from near the top surface of the PS layer and the 420 nm luminescence the interface between the PS layer and Si substrate. The increase of the 420 nm luminescence intensity upon removal of the Si substrate suggests that the excited carriers in the residual Si matrix of the PS take part in the 420 nm luminescence.
Japanese Journal of Applied Physics, 1994
Microstructure and crystallinity of a porous silicon (PS) layer formed on a highly doped n-type s... more Microstructure and crystallinity of a porous silicon (PS) layer formed on a highly doped n-type silicon substrate were examined in detail, and the luminescent nature of the PS layer was also studied qualitatively. A layered pore structure developed after about 3000 s of anodization, and pore morphology became simpler with increasing thickness of the PS layer. All luminescent PS layers were found to show spongelike structure near the surface. From the peak width of X-ray rocking curves, the crystallinity of n-type PS was found to be inferior to that of p-type PS. No systemic tendency of the lattice expansion was seen under various forming current densities. Luminescent PS layers showed slightly broader background intensity than nonluminescent ones. It was also shown that the anodization of the PS layer took place through two anodization processes: primary and secondary anodizations; secondary anodization was effective in forming luminescent parts having spongelike structure.
Japanese Journal of Applied Physics, 1994
Cathodoluminescence (CL) from n-type porous silicon was studied using the CL detection system com... more Cathodoluminescence (CL) from n-type porous silicon was studied using the CL detection system combined with a transmission electron microscope. Two luminescence bands were observed with peaks at 420 nm and 660 nm. The 660 nm band peak decays more quickly with increasing accelerating voltage and decreasing temperature. The intensity profile along the cross-sectional trace shows that the 660 nm luminescence centers are mainly located near the top side of the porous layer. The 420 nm CL band was found at accelerating voltage higher than 160 kV at 20 K.
Nihon Kessho Gakkaishi, 1993
Japanese journal of …, 1999
A transmission X-ray microscope having two zone plates has been developed at BL-12, Ritsumeikan S... more A transmission X-ray microscope having two zone plates has been developed at BL-12, Ritsumeikan Synchrotron Radiation Center (Rits SR Center). By incorporating a new type of condenser zone plate (diameter 9 mm, zone number 41,890, outermost zone width ...
Uploads
Papers by kuniko takemoto