RYO YOKOGAWA

Last Updated :2026/08/06

Affiliations, Positions
Research Institute for Semiconductor Engineering, Assistant Professor
E-mail
yokogawahiroshima-u.ac.jp

Basic Information

Academic Degrees

  • Meiji University
  • Meiji University

Educational Activity

Course in Charge

  1. 2026, Undergraduate Education, First Semester, Experiments in Electrical Engineering Electronics and System Engineering I
  2. 2026, Undergraduate Education, First Semester, Experiments in Electrical Engineering Electronics and System Engineering I
  3. 2026, Undergraduate Education, Second Semester, Experiments in Electrical Engineering Electronics and System Engineering II
  4. 2026, Undergraduate Education, Second Semester, Experiments in Electrical Engineering Electronics and System Engineering II
  5. 2026, Undergraduate Education, First Semester, Basic Experiments in Electrical Engineering I
  6. 2026, Undergraduate Education, First Semester, Basic Experiments in Electrical Engineering I
  7. 2026, Undergraduate Education, Second Semester, Basic Experiments in Electrical Engineering II
  8. 2026, Undergraduate Education, Second Semester, Basic Experiments in Electrical Engineering II

Research Activities

Academic Papers

  1. Local vibrational properties of bulk single-crystal Si1-xGex studied by XAS and SAXS, Materials Science in Semiconductor Processing, 212, 110812-110812, 20260901
    Link to Paper Search Results by DOI
  2. Raman study on Si1-xSnx epitaxial layers to determine the composition-and strain-shift coefficients, MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 214, 20261101
    Link to Paper Search Results by DOI
  3. Ge heteroepitaxy on Si(111) substrate featuring sputtering method, MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 210, 20260801
    Link to Paper Search Results by DOI
  4. Correlation between low-energy localized phonon mode intensity and Ge cluster size in SiGe alloys, MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 210, 20260801
    Link to Paper Search Results by DOI
  5. Formation of two-dimensional-like Ge1-ySny ultra-thin crystal by segregation method, JAPANESE JOURNAL OF APPLIED PHYSICS, 65(5), 20260316
    Link to Paper Search Results by DOI
  6. Healing Atom Vacancy and Oxidation Suppression in Solution-Processed MoS2 through Sulfur Vapor Annealing, ACS APPLIED MATERIALS & INTERFACES, 18(3), 6088-6097, 202601
    Link to Paper Search Results by DOI
  7. Area-Selective Atomic Layer Deposition of Ruthenium on SiO2/W Patterns Using Silicon-Based Inhibitors, ECS Journal of Solid State Science and Technology, 15(1), 202601
    Link to Paper Search Results by DOI
  8. ★, Spatial correlation model for Si-rich SiGe alloys based on Raman spectra, Japanese Journal of Applied Physics, 64, 060904-060904, 202506
  9. Evaluation of temperature dependent stress around electrodes in crystalline silicon solar cells by Raman spectroscopy, Japanese Journal of Applied Physics, 64(6), 06SP11-06SP11, 202506
  10. Evaluation of Ag-coated Cu paste as Ag-saving electrode paste for silicon heterojunction solar cells, JAPANESE JOURNAL OF APPLIED PHYSICS, 64(5), 20250501
    Link to Paper Search Results by DOI
  11. Evaluation of Ag-coated Cu paste as Ag-saving electrode paste for silicon heterojunction solar cells, Japanese Journal of Applied Physics, 64(5), 05SP12-05SP12, 202505
  12. Evaluation of bias-dependent band structure changes in metal–oxide–semiconductor structures with varying doping concentrations using laboratory hard x-ray photoelectron spectroscopy, Applied Physics Letters, 126(7), 072103-072103, 202503
  13. Temperature and Ge fraction dependence of broad peaks observed in Ge-rich SiGe Raman spectra by oil-immersion Raman spectroscopy, Japanese Journal of Applied Physics, 63(12), 125504-125504, 202412
  14. Evaluation of Band Structure of Single Crystalline Si-Rich SiSn thin Film, ECS Transactions, 114(2), 225-232, 20240927
  15. Optical Properties of Multilayered Staggered SiGe Nanodots Depending on Si Spacer Growth Temperature, ECS Transactions, 114(2), 207-214, 20240927
  16. ★, Determination of Ge-fraction-shift coefficients for Raman spectroscopy in all vibration modes investigated by single-crystalline bulk SiGe and its application to strain evaluation in SiGe film grown on substrate, Japanese Journal of Applied Physics, 63(3), 035503-035503, 202403
  17. Strain and optical characteristics analyses of three-dimentional self-ordered multilayered SiGe nanodots by photoluminescence and Raman spectroscopy, Japanese Journal of Applied Physics, 63(3), 03SP31-03SP31, 202402
  18. Local thermal conductivity properties of a SiGe nanowire observed by laser power sweep Raman spectroscopy, Japanese Journal of Applied Physics, 63(2), 02SP68-02SP68, 202401
  19. Strain distributions in carbon-doped silicon nanowires along [110] and [100] investigated by X-ray diffraction, Japanese Journal of Applied Physics, 63(1), 01SP11-01SP11, 202312
  20. Evaluation of Anisotropic Biaxial Stress in Extremely-Thin Body (100) Silicon-Germanium-on-Insulator p-Type Metal-Oxide-Semiconductor Field-Effect-Transistor by Oil-Immersion Raman Spectroscopy, ECS Transactions, 112(1), 37-43, 202309
  21. Temperature Dependence of Raman Peak Shift in Single-Crystalline Silicon-Germanium, ECS Journal of Solid State Science and Technology, 12(6), 064004-064004, 202306
  22. Analysis of InGaAs/InP p-I-n Photodiode Failed by Electrostatic Discharge, Journal of Electronic Materials, 52(8), 5150-5158, 20230524
  23. Evaluation of Strain-Relaxation of Carbon-Doped Silicon Nanowires and Its Crystal Orientation Dependence Using X-Ray Diffraction Reciprocal Space Mapping, Journal of Electronic Materials, 52(8), 5140-5149, 20230523
  24. Inelastic X-ray Scattering Measurement on Single-Crystalline GeSn Thin Film, Journal of Electronic Materials, 52(8), 5128-5133, 20230508
  25. Conformal deposition of WS2 layered film by low-temperature metal-organic chemical vapor deposition, Japanese Journal of Applied Physics, 62(SG), SG1048-SG1048, 202305
  26. Effect of sawing damage on flexibility of crystalline silicon wafers for thin flexible silicon solar cells, Japanese Journal of Applied Physics, 62(1), 20230101
  27. Non-seed chemical bath deposition of ZnO films in a rotating continuous flow reactor with various carboxylic acids and their application to transparent conductive films, CRYSTENGCOMM, 24(47), 8294-8302, 202212
  28. Distribution Evaluation of Optical Properties in Silicon Germanium Films Grown on Silicon Substrates with Graded Silicon Germanium Buffer Layers, ECS Transactions, 109(4), 367-374, 20220930
  29. Investigation of Band Structure in Strained Single Crystalline Si1-X Sn X , ECS Transactions, 109(4), 359-366, 20220930
  30. Evaluation of Strained Group IV Semiconductor Devices by Oil-Immersion Raman Spectroscopy, ECS Transactions, 109(4), 351-357, 202209
  31. ★, Study on phonon lifetime in bulk silicon–germanium through observation of acoustic phonon spectra broadening by inelastic x-ray scattering, Applied Physics Letters, 121(8), 082105-082105, 20220822
  32. Modification and Characterization of Interfacial Bonding for Thermal Management of Ruthenium Interconnects in Next-Generation Very-Large-Scale Integration Circuits, ACS Applied Materials and Interfaces, 14(5), 7392-7404, 20220209
  33. Atomic mass dependency of a localized phonon mode in SiGe alloys, AIP Advances, 11(11), 115225-115225, 202111
  34. Dependency of a localized phonon mode intensity on compositional cluster size in SiGe alloys, AIP Advances, 11(7), 075017-075017, 202107
  35. Thermal conductivity and inelastic X-ray scattering measurements on SiGeSn polycrystalline alloy, Japanese Journal of Applied Physics, 60(SB), SBBF11-SBBF11, 202105
  36. Phonon properties of group IV materials for thermoelectric applications, 2021 5th IEEE Electron Devices Technology and Manufacturing Conference, EDTM 2021, 20210408
  37. Effect of Growth Parameters on MoS2Film Quality Deposited by Low-Temperature MOCVD Using I-Pr2DADmo(CO)3and (t-C4H9)2S2, ECS Transactions, 104(3), 3-15, 2021
  38. Evaluation of Mo(1-x)W xs Alloy Fabricated by Combinatorial Film Deposition, ECS Transactions, 104(3), 21-28, 2021
  39. Strain evaluation in Ge and Sn implanted Si layers with laser and rapid thermal annealing, Materials Science in Semiconductor Processing, 120, 105282-105282, 202012
  40. Origin of carrier lifetime degradation in floating-zone silicon during a high-temperature process for insulated gate bipolar transistor, Japanese Journal of Applied Physics, 59(11), 115503-1-115503-6, 202011
  41. Evaluation of Thermal Conductivity Characteristics in Polycrystalline Silicon - The Effect of Nanostructure in the Grains, ECS Transactions, 98(5), 437-446, 202009
  42. Evaluation of Silicon Nitride Film Formed by Atomic Layer Deposition on the Silicon Substrate with Trench Structure Using Angle-Resolved Hard X-ray Photoelectron Spectroscopy, ECS Transactions, 98(3), 113-120, 202009
  43. Evaluation of Thermal Expansion Coefficient in Ge1-x Sn x Nanowire Using Reciprocal Space Mapping, ECS Transactions, 98(5), 481-490, 202009
  44. Evaluation of Temperature and Germanium Concentration Dependence of EXAFS Oscillations in Si-Rich Silicon Germanium Thin Films, ECS Transactions, 98(5), 473-479, 202009
  45. Observation of an Unidentified Phonon Peak in SiGe Alloys and Superlattices Using Molecular Dynamics Simulation, ECS Transactions, 98(5), 533-546, 202009
  46. Evaluation of Strain-Shift Coefficients for SiSn by Raman Spectroscopy, ECS Transactions, 98(5), 291-300, 202009
  47. Evaluation of Phonon Dispersion Relation for Bulk Silicon Germanium by Inelastic X-ray Scattering, ECS Transactions, 98(5), 465-472, 202009
  48. Quantification of Ge fraction using local vibrational modes in Raman spectra of silicon germanium by oil-immersion Raman spectroscopy, Japanese Journal of Applied Physics, 59(7), 075502-075502, 20200701
  49. ★, Anomalous low energy phonon dispersion in bulk silicon-germanium observed by inelastic x-ray scattering, Applied Physics Letters, 116(24), 242104-242104, 20200615
  50. Evaluation of Sawing Damage for Thin Flexible Silicon Solar Cells, Conference Record of the IEEE Photovoltaic Specialists Conference, 2020-June, 0875-0880, 20200614
  51. Phonon dispersion of bulk Ge-rich SiGe: inelastic X-ray scattering studies, Japanese Journal of Applied Physics, 59(6), 061003-1-061003-6, 202006
  52. Stress evaluation induced by wiggling silicon nitride fine pattern using Raman spectroscopy, Japanese Journal of Applied Physics, 59(SI), SIIF03-1-SIIF03-6, 202006
  53. Thermal conductivity characteristics in polycrystalline silicon with different average sizes of grain and nanostructures in the grains by UV Raman spectroscopy, Japanese Journal of Applied Physics, 59(7), 075501-1-075501-7, 202005
  54. Anisotropic biaxial stress evaluation in metal-organic chemical vapor deposition grown Ge1-xSnx mesa structure by oil-immersion Raman spectroscopy, Thin Solid Films, 697, 137797-1-137797-5, 202003
  55. Anisotropic Biaxial Strain Evaluation in Carbon-Doped Silicon Using Water-Immersion Raman Spectroscopy, ECS Transactions, 92(4), 33-39, 201907
  56. Ultra-Thin Lightweight Bendable Crystalline Si Solar Cells for Solar Vehicles, Conference Record of the IEEE Photovoltaic Specialists Conference, 1131-1134, 201906
  57. Evaluation of thermal conductivity characteristics in Si nanowire covered with oxide by UV Raman spectroscopy, Japanese Journal of Applied Physics, 58(SD), SDDF04-1-SDDF04-5, 201906
  58. Evaluations of minority carrier lifetime in floating zone Si affected by Si insulated gate bipolar transistor processes, Japanese Journal of Applied Physics, 58(SB), SBBD07-1-SBBD07-6, 201904
  59. Determination of phonon deformation potentials and strain-shift coefficients in Ge-rich Si1-xGex using bulk Ge-rich Si1-xGex crystals and oil-immersion Raman spectroscopy, JAPANESE JOURNAL OF APPLIED PHYSICS, 57(10), 106601-1-106601-6, 201810
  60. Strain Evaluation of Laser-annealed SiGe Thin Layers, ECS Transactions, 86(7), 59-65, 201809
  61. Determination of Phonon Deformation Potentials in Carbon-doped Silicon, ECS Transactions, 86(7), 419-425, 201809
  62. Evaluation of Anisotropic Three-Dimensional Strain Relaxation in Stripe-Shaped Ge1-xSnx Mesa Structure, ECS Transactions, 86(7), 329-336, 201809
  63. Evaluation of Laterally Graded Silicon Germanium Wires for Thermoelectric Devices Fabricated by Rapid Melting Growth, ECS Transactions, 86(7), 87-93, 201809
  64. Evaluation of Anisotropic Biaxial Stress Induced Around Trench Gate of Si Power Transistor Using Water-Immersion Raman Spectroscopy, Journal of Electronic Materials, 47, 1-6, 20180503
  65. Miniaturized planar Si-nanowire micro-thermoelectric generator using exuded thermal field for power generation, Science and Technology of Advanced Materials, 19(1), 443-453, 201805
  66. Probing spatial heterogeneity in silicon thin films by Raman spectroscopy, Scientific Reports, 7, 16549-1-16549-8, 201711
  67. Local anisotropic strain evaluation in thin Ge epitaxial film using SiGe stressor template grown on Ge substrate by selective ion implantation, Japanese Journal of Applied Physics, 56(11), 110313-1-110313-4, 20171101
  68. Enhanced nickelidation rate in silicon nanowires with interfacial lattice disorder, Journal of Applied Physics, 122(14), 144305-1-144305-7, 201710
  69. Evaluation of controlled strain in silicon nanowire by UV Raman spectroscopy, Japanese Journal of Applied Physics, 56(6), 06GG10-1-06GG10-5, 20170601
  70. Biaxial stress evaluation in GeSn film epitaxially grown on Ge substrate by oil-immersion Raman spectroscopy, Japanese Journal of Applied Physics, 55(9), 091301-1-091301-4, 20160901
  71. Origin of additional broad peaks in Raman spectra from thin germanium-rich silicon-germanium films, Applied Physics Express, 9(7), 071301-1-071301-4, 20160701
  72. In-plane biaxial strain evaluation induced in Ge1-xSnx films using oil-immersion raman spectroscopy, ECS Transactions, 75(8), 589-597, 2016
  73. Crystallinity evaluation of low temperature polycrystalline silicon thin film using UV/visible Raman spectroscopy, ECS Transactions, 72(4), 249-255, 2016
  74. Evaluation of anisotropic biaxial stress in Si1-xGex/Ge mesa-structure by oil-immersion raman spectroscopy, ECS Transactions, 66(4), 39-45, 2015
  75. On the origin of the gate oxide failure evaluated by Raman spectroscopy, ECS Transactions, 66(4), 237-243, 2015
  76. Evaluation of Anisotropic Biaxial Stress in Thin Strained-SiGe Layer Using Surface Enhanced Raman Spectroscopy, ECS Transactions, 64(6), 841-847, 201410
  77. Temperature and Ge fraction dependence of broad peaks observed in Ge-rich SiGe Raman spectra by oil-immersion Raman spectroscopy, JAPANESE JOURNAL OF APPLIED PHYSICS, 63(12), 20241202
    Link to Paper Search Results by DOI

Invited Lecture, Oral Presentation, Poster Presentation

  1. Microscopic study on ​ group IV semiconductor alloys using synchrotron radiation, Ryo Yokogawa, Hiroshima University J-PEAKS International Symposium 2026: New Frontiers through Interdisciplinary Research Integration — Focusing on Synchrotron Radiation Science —, 2026/03/02, With Invitation, English
  2. Study on phonon properties and atomic arrangement of SiGe alloy using synchrotron radiation techniques, Ryo Yokogawa, The 30th Hiroshima International Symposium on Synchrotron Radiation, 2026/03/04, With Invitation, English
  3. Role of Annealing Atmosphere Towards Stoichiometry and Chemical Integrity of Solution-Processed MoS2 Thin films, Md Iftekharul Alam, Shungo Nagata, Jaehyo Jang, Hayato Kosaka, Naoki Matsunaga, Yoshiteru Amemiya, Ryo Yokogawa, Hitoshi Wakabayashi, Akinobu Teramoto, IWDTF2025, 2025/11/07, Without Invitation, English
  4. Segregation induced formation of two-dimensional like GeSn ultra-thin crystal, Shigehisa Shibayama, Taiga Mtasumoto, Akio Ohta, Ryo Yokogawa, Mitsuo Sakashita, Masashi Kurosawa, Osamu Nakatsuka, IWDTF2025, 2025/11/07, English
  5. Roughness Resistance of Si(551) Surface under Wet Cleaning Evaluation toward Next-Generation CMOS Technologies, Nawaphorn Kuhakongkia, Shungo Nagata, Akihiro Suzuki, Hiroaki Yamamoto, Kazuhito Matsukawa, Koji Matsumoto, Ryo Yokogawa, Akinobu Teramoto, IWDTF2025, 2025/11/06, Without Invitation, English
  6. Strain Effect of Multilayered Dot-on-Dot Ge Nanodots Embedded in SiGe Spacers, Yuta Ito, Ryo Yokogawa, Wei-Chen Wen, Yuji Yamamoto, Naomi Sawamoto, Hiromu Kudo, Atsushi Ogura, 248th ECS Meeting, 2025/10/15, Without Invitation, English
  7. High Quality ZrxHf1-XS2 Alloy Film Fabrication By Co-Sputtering Using Powder HfS2 and Sintered ZrS2 Targets with H2s Annealing, Taichi Ishikawa, Koki Hori, Naoya Okada, Naomi Sawamoto, Ryo Yokogawa, Atsushi Ogura, 248th ECS Meeting, 2025/10/14, Without Invitation, English
  8. Physical Evaluation of Sputtered Ge Layer on Si(111) for Ge Ultra-Thin Crystal Formation Process, Ryo Yokogawa, Yuta Ito, Taichi Okuda, Shigehisa Shibayama, Osamu Nakatsuka, Atsushi Ogura, 248th ECS Meeting, 2025/10/14, Without Invitation, English
  9. Area Selective Atomic Layer Deposition of Ruthenium on SiO2 and W, Shogo Okugawa, Rahman Gagi, Ryo Yokogawa, Yoshiteru Amemiya, Akinobu Teramoto, 248th ECS Meeting, 2022/10/13, Without Invitation, English
  10. Phase-Control Fabrication of MoTe2 by RF Magnetron Sputtering and Tellurization by Annealing in (i-C3H7)2Te Atmosphere, Sota Higashi, Daiki Nakanishi, Taichi Ishikawa, Hiroshi Yokota, Ryo Yokogawa, Hideaki Machida, Masato Ishikawa, Hiroshi Sudoh, Atsushi Ogura, 248th ECS Meeting, 2025/10/13, Without Invitation, English

Social Activities

History as Committee Members

  1. Steering Committee, 2025/11, SSDM2026
  2. Steering Committee, 2024/12, International Workshop on Dielectric Thin Films (IWDTF) 2025
  3. Organizing Committee, 2021, 2022, 19th International Conference on Defects-Recognition, Imaging and Physics in Semiconductors (DRIP XIX)

History as Peer Reviews of Academic Papers

  1. 2026, Japanese Journal of Applied Physics, Others, Referee
  2. 2025, IEEE Journal of the Electron Devices Society, Others, Referee
  3. 2025, Silicon, Others, Referee
  4. 2024, Applied Physics Letter, Others, Referee
  5. 2023, Journal of Electronic Materials, Others, Referee
  6. 2020, Japanese Journal of Applied Physics, Others, Referee
  7. 2020, ACS Omega, Others, Referee