The Physical origin of the InSb(111)A surface reconstruction transient

Proessdorf, A.*; Rodenbach, P.*; Grosse, F.*; Hanke, M.*; Braun, W.*; Riechert, H.*; Hu, W.; Fujikawa, Seiji*; Kozu, Miwa; Takahashi, Masamitsu

Surface Science, 606(17-18), p.1458 - 1461, 2012/09

https://doi.org/10.1016/j.susc.2012.05.017

Growth temperature dependence of strain relaxation during InGaAs/GaAs(0 0 1) heteroepitaxy

Sasaki, Takuo*; Suzuki, Hidetoshi*; Sai, Akihisa*; Takahashi, Masamitsu; Fujikawa, Seiji; Kamiya, Itaru*; Oshita, Yoshio*; Yamaguchi, Masafumi*

Journal of Crystal Growth, 323(1), p.13 - 16, 2011/05

https://doi.org/10.1016/j.jcrysgro.2010.10.005

Growth temperature dependence of strain relaxation during InGaAs/GaAs(001) molecular beam epitaxy was studied by in situ X-ray reciprocal space mapping. Evolution of the residual strain and crystal quality for the InGaAs film was obtained as a function of film thickness at growth temperatures of 420, 445 and 477 C. In the early stages of strain relaxation, it was found that evolution of the residual strain and crystal quality was dependent on the growth temperature. In order to discuss this observation quantitatively, the strain relaxation model was proposed based on the Dodson-Tsao kinetic model, and its validity was demonstrated by good agreement with the experimental residual strain. Additionally, rate coefficients reflecting dislocation motions during strain relaxation were obtained as a function of growth temperature and strain relaxation was discussed in terms of the thermally active dislocation motion.

Structural changes caused by quenching of InAs/GaAs(001) quantum dots

Takahashi, Masamitsu; Fujikawa, Seiji

Japanese Journal of Applied Physics, 50(4), p.04DH06_1 - 04DH06_5, 2011/04

https://doi.org/10.1143/JJAP.50.04DH06

Time-resolved X-ray diffraction measurements of high-density InAs quantum dots on Sb/GaAs layers and the suppression of coalescence by Sb-irradiated growth interruption

Kakuda, Naoki*; Kaizu, Toshiyuki*; Takahashi, Masamitsu; Fujikawa, Seiji; Yamaguchi, Koichi*

Japanese Journal of Applied Physics, 49(9), p.095602_1 - 095602_4, 2010/09

https://doi.org/10.1143/JJAP.49.095602

In situ study of strain relaxation mechanisms during lattice-mismatched InGaAs/GaAs growth by X-ray reciprocal space mapping

Sasaki, Takuo*; Suzuki, Hidetoshi*; Sai, Akihisa*; Takahashi, Masamitsu; Fujikawa, Seiji; Oshita, Yoshio*; Yamaguchi, Masafumi*

Materials Research Society Symposium Proceedings, Vol.1268, 6 Pages, 2010/05

https://doi.org/10.1557/PROC-1268-EE06-02

In situ observation of InP(001) growth under metalorganic chemical vapor deposition using synchrotron radiation source

Fujikawa, Seiji; Kawamura, Tomoaki*; Bhunia, S.*; Watanabe, Yoshio*

no journal, , 

Growth mechanism of InP(001) of metalorganic chemical vapor deposition has been studied by X-ray reflectivity and grazing incidence X-ray diffraction (GIXD). The changes of reflectivity signal suggested that growth mode depended on substrate temperature, and particularly the step-flow growth mode was dominant at more than 550C. Monitoring the fractional-order reflection of (21)-InP(001) using GIXD during the step-flow growth, the changes of fractional-order reflection suggested that indium atom migrate on the substrate surface more than 1 minute during the growth.

In situ Observation of growth mechanisms of bcc-Fe on GaAs(001) and InAs(001) by using Grazing Incidence X-ray Diffraction

Fujikawa, Seiji; Takahashi, Masamitsu

no journal, , 

no abstracts in English

In situ observation of Fe growth on GaAs(001) and InAs(001) by X-ray diffraction

Fujikawa, Seiji; Takahashi, Masamitsu

no journal, , 

In this work, we evaluated Fe films on GaAs(001) and InAs(001) by in-situ X-ray diffraction measurements with increasing Fe thickness. While the Fe film on InAs(001) was strained even at 30 ML, Fe on GaAs(001) was already relaxed at 4 ML with FeGaAs2 diffraction. While the increase of FeGaAs2 intensity shows down at 12 ML, The intensity of Fe 020 increasingly rises. These results suggest that interfacial FeGaAs22 on GaAs(001) facilitate the strain relief of Fe/GaAs(001).

X-ray diffraction study on hydrogen-induced Pd(110) surface reconstruction

Takahashi, Masamitsu; Fujikawa, Seiji*; Hu, W.; Tajiri, Hiroo*

no journal, , 

Absorption of hydrogen into a substrate begins with dissociated adsorption of hydrogen molecules. The mechanism of the transition from adsorption to absorption is an important knowledge for improving the performance of hydrogen storage materials. The aim of the present study is to verify the hydrogen absorption model in atomic scale through quantitative determination of structures of hydrogen-adsorbed Pd(110) by synchrotron X-ray diffraction. Experiments were performed at a synchrotron beamline 13XU at SPring-8 using a surface X-ray diffractometer integrated with a UHV chamber equipped with a cryostat. We measured five crystal truncation rod (CTR) profiles with increasing substrate temperature to room temperature from 57 K after the substrate was exposed to 10 Torr s hydrogen. Results show an atomic-scale picture that explains how adsorbed hydrogen is absorbed into the Pd bulk.

High interface spin polarization and its mechanism in fullerene-magnetic metal systems

Sakai, Seiji; Mitani, Seiji*; Matsumoto, Yoshihiro; Otomo, Manabu; Entani, Shiro; Avramov, P.; Naramoto, Hiroshi*; Fujikawa, Takashi*

no journal, ,