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- T. Hashimoto, R. Oshima, H. Shigekawa, and Y. Okada, "MBE growth of InAs self-assembled quantum dots embedded in GaNAs strain-compensating layers", 14th International Conference on Molecular Beam Epitaxy, Waseda (September 2006).
- Y. Shimizu, N. Miyashita, Y. Mura, A. Uedono, and Y. Okada, "Effect of growth temperature on the properties of Ga(In)NAs thin films by atomic hydrogen-assisted RF-MBE", 14th International Conference on Molecular Beam Epitaxy, Waseda (September 2006).
- R. Oshima, K. Akahane, M. Tsuchiya, H. Shigekawa, and Y. Okada, "Optical properties of stacked InAs self-organized quantum dots on InP (311)B", 14th International Conference on Molecular Beam Epitaxy, Waseda (September 2006).
- R. Oshima, T. Hashimoto, H. Shigekawa, and Y. Okada, "InAs self-assembled quantum dots superlattice structure fabricated by strain compensation technique", 28th International Conference on Physics of Semiconductors, Vienna (July 2006).
- N. Miyashita, Y. Shimizu, N. Kobayashi, M. Yamaguchi, and Y. Okada, "Fabrication of GaInNAs-based Solar Cells for Application to Multi-junction Tandem Solar Cells", 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4), Hawaii (May 2006).
- Y. Shimizu, N. Miyashita, Y. Mura, A. Uedono, and Y. Okada, "Optimization of Growth of GaInNAs Dilute Nitrides for Multi-junction Solar Cell Applications", 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4), Hawaii (May 2006).
- R. Oshima, H. Komiyama, T. Hashimoto, H. Shigekawa, and Y. Okada, "Fabrication of Multi-layer Self-assembled InAs Quantum Dots for High-Efficiency Solar Cells", 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4), Hawaii (May 2006).
- Y. Okada, N. Kobayashi, and N. Sasaki, "Improvement of Below-Bandgap Photoabsorption in GaAs Solar Cells Using GaAs/GaNAs/InGaAs Quantum Wells", 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4), Hawaii (May 2006).
- N. Kobayashi, N. Sasaki, and Y. Okada, "Potentially Modulated GaAs/GaNAs/InGaAs Quantum Wells for Solar Cell Applications", 2005 MRS Fall Meeting, Boston (Nov. 2005).
- Y. Shimizu, N. Miyashita, A. Uedono, and Y. Okada, "Optimization of Growth Temperature of Ga(In)NAs Thin Films Grown by Atomic Hydrogen-assisted RF-MBE", 2005 MRS Fall Meeting, Boston (Nov. 2005).
- R. Oshima, T. Hashimoto, H. Shigekawa and Y. Okada, "Effect of Strain Compensation on Multi-stacking of InAs Self-assembled Quantum Dots Embedded in GaNAs Layers", 2005 MRS Fall Meeting, Boston (Nov. 2005).
- N. Kobayashi, N. Miyashita, Y. Shimizu, and Y. Okada, "Fabrication of GaAs/GaInNAs Heterojunction Solar Cells Applicable To High-Efficiency Multi-junction Tandem Structure", 2005 International Conference on Solid State Devices and Materials (ssdm), Kobe (Sept. 2005).
- R. Oshima, T. Hashimoto, H. Shigekawa and Y. Okada, "Long wavelength InAs self-assembled quantum dots embedded in GaNAs strain compensating layers", 12th International Conference on Modulated Semiconductor Structures (MSS-12), Albuquerque (July 2005).
- R. Oshima, T. Hashimoto, H. Shigekawa and Y. Okada, "1.3um Emission from InAs Self-assembled Quantum Dots embedded in GaNAs Strain-compensating Layers", International Symposium on Quantum Dots and Photonic Crystals 2005, Tokyo (March 2005).
- Y. Okada, and N. Shiotsuka, "Fabrication of Potentially Modulated Multi-Quantum Well Solar Cells", 31st IEEE Photovoltaic Specialists Conference, Walt Disney Resort (Jan. 2005).
- Y. Okada, Y. Shimizu, N. Kobayashi, and A. Uedono, "Effect of atomic hydrogen on the growth of GaInNAs thin films by RF-MBE", 2004 International Conference on Molecular Beam Epitaxy, Edinburgh (Aug. 2004).
- R. Oshima, K. Uehara, H. Shigekawa, and Y. Okada, "Fabrication of self-organized GaInNAs quantum dots on GaAs (311)B by atomic hydrogen-assisted RF- molecular beam epitaxy", 2004 International Conference on Compound Semiconductors, Seoul (Sept. 2004).
- Y. Shimizu, N. Kobayashi, A. Uedono, and Y. Okada, "Defect control in Ga(In)NAs films grown by atomic H assisted RF-MBE", 2004 International Conference on Compound Semiconductors, Seoul (Sept. 2004).
- Y. Okada, R. Oshima, and H. Shigekawa, "Electronic States of Self-Organized InGaAs Quantum Dots Studied by Conductive Scanning Probe Microscope", 1st International Tsukuba-Symposium on "Nanoscience" (ITNs 2003), Tsukuba (Nov. 2003).
- R. Oshima and Y. Okada, "Growth of self-assembled GaInNAs quantum dots by atomic-H assisted RF molecular beam epitaxy", 7th International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures (ACSIN-7), Nara (Nov. 2003).
- R. Oshima, N. Kurihara, H. Shigekawa, and Y. Okada, "Electronic States of Self-Organized InGaAs Quantum Dots on GaAs (311)B Studied by Conductive Probe Microscope", 11th International Conference on Modulated Semiconductor Structures (MSS-11), Nara (July 2003).
- H. Z. Song, Y. Nakata, Y. Okada, T. Miyazawa, T. Ohshima, M. Takatsu, M. Kawabe, and N. Yokoyama, "Growth Process of Quantum Dots Precisely Controlled by an AFM Assisted Technique", 11th International Conference on Modulated Semiconductor Structures (MSS-11), Nara (July 2003).
- H. Z. Song, Y. Nakata, Y. Okada, T. Miyazawa, T. Ohshima, M. Kawabe, and N. Yokoyama, "Quantum Dot Fabrication for Quantum Computing: An AFM-Assisted Technique", International Symposium on Nanotechnology for Photonics and Optoelectronics (NPO-2003), Tokyo (March 2003).
- N. Shiotsuka, T. Takeda, and Y. Okada, "Potentially Modulated Multi-Quantum Wells with Improved dark Current Characteristics", 3rd World Conference on Photovoltaic Energy Conversion (WCPEC-3), Osaka (May 2003).
- Y. Shimizu and Y. Okada, "GaAs/Si Solar Cells with Internal Bragg Reflector Superlattice Structure", 3rd World Conference on Photovoltaic Energy Conversion (WCPEC-3), Osaka (May 2003).
- Y. Okada, N. Matsumoto, and A. Ohmae, "GaInNAs for Multi-Junction Tandem Solar cells", 3rd World Conference on Photovoltaic Energy Conversion (WCPEC-3), Osaka (May 2003).
- Y. Okada and R. Oshima, gStacked Quamtum Dots for Use in
Higher Efficiency Photovoltaic Devicesh, MRS 2002 Fall Meeting, Boston,
Dec. 2002.

- (Invited) Y. Okada, K. Akahane, and M. Kawabe,
gHigh-density self-organized quantum dots with improved size uniformity
for optical device applicationsh, SPIE Photonics-Asia 2002, Shanghai,
Oct. 2002.

- A. Ohmae, N. Matsumoto, and Y. Okada, gGrowth of GaInNAs
by Atomic Hydrogen-Assisted RF-MBEh, 12th International Conference on
Molecular Beam Epitaxy, San Francisco, Sept. 2002.

- A. Ohmae, N. Matsumoto, K. Kawabe, and Y. Okada, gEffects
of Atomic Hydrogen on the Growth of Ga(In)NAs by RF-MBEh, 2002
International Workshop on Nitride Semiconductors, Aachen, July 2002.

- H. Z. Song, T. Ohshima, Y. Okada, K. Akahane, T. Miyazawa,
M. Kawabe, and N. Yokoyama, gFinely Controlling Quantum Dots on GaAs
Surface Patterned by Removing Oxide Dots Formed in Atomic Force
Microscope Lithographyh, 26th International Conference on the Physics
of Semiconductors, Edinburgh, July 2002.

- R. Oshima, K. Akahane, M. Kawabe, and Y. Okada,
gTemperature dependence of photoluminescence from long-wavelength
InGaAs quantum dots on GaAs (311)B substrate grown with strain-reducing
layersh, 2nd International Workshop on Quantum Nonplanar Nanostructures
& Nanoelectronics, Tsukuba, Sept. 2002.

- K. Akahane, N. Yamamoto, N. Ohtani, Y. Okada, and M.
Kawabe, gRole of Al in strain-compensating spacer layer of stacked InAs
quantum dot structures on InP (311)h, 2nd International Workshop on
Quantum Nonplanar Nanostructures & Nanoelectronics, Tsukuba,
Sept. 2002.

- H. Z. Song, T. Ohshima, Y. Okada, K. Akahane, M. Kawabe,
T. Miyazawa, and N. Yokoyama, gAFM-assisted control of self-assembled
quantum dotsh, 2nd International Workshop on Quantum Nonplanar
Nanostructures & Nanoelectronics, Tsukuba, Sept. 2002.

- Y. Okada, T. Takeda, and M. Kawabe, gControl of Dark
Currents in Multi-Quantum Well Solar Cells By Use of Thin Tunnel
Barriersh, 29th IEEE Photovoltaic Specialists Conference, New Orleans,
May 2002.

- Y. Okada, M. Miyagi, H. Shigekawa, and M. Kawabe,
gElectronic properties of self-organized InGaAs quantum dots on
GaAs(311)B substrates studied by conductive AFMh, International
Colloquium on Scanning Probe Microscopy, Atagawa, Dec. 2001.

- H. Z. Song, Y. Okada, K. Akahane, H. Z. Xu, and M. Kawabe,
gNegative differential conductance of InxGa1-xAs/GaAs(311)B laterally
coupled quantum dotsh, 28th International Symposium on Compound
Semiconductors, Tokyo, Oct. 2001.

- M. Miyagi, K. Akahane, H. Shigekawa, M. Kawabe, and Y.
Okada, gTransport through InGaAs/GaAs(311)B Quantum Dots Studied by
Conductive Scanning Probesh, 28th International Symposium on Compound
Semiconductors, Tokyo, Oct. 2001.

- J. Takamori, Y. Shimizu, T. Ueda, C. Yamagishi, M. Kawabe,
and Y. Okada, gOptimization of GaAs/Si Heteroepitaxy for Solar Cell
Applicationh, 28th International Symposium on Compound Semiconductors,
Tokyo, Oct. 2001.

- K. Akahane, H. Z. Xu, H. Z. Song, Y. Okada, and M. Kawabe,
gUniform stacked InAs quantum dots by strain control on InP (311)B
substrateh, 1st International Workshop on Quantum Nonplanar
Nanostructures & Nanoelectronics, Tsukuba, July 2001.

- Y. Okada, S. Seki, T. Takeda, and M. Kawabe, gControl of
Dark Currents in Multi-Quantum Well Solar Cells Fabricated by Atomic
H-Assisted Molecular Beam Epitaxyh, 13th International Conference on
Crystal Growth, Kyoto, July 2001.

- K. Akahane, H. Z. Song, Y. Okada, and M. Kawabe, gInGaAs
Quantum Dots Embedded in p-n Junction on GaAs (311)B substrateh, MRS
2000 Fall Meeting, Boston, Nov. 2000.

- Y. Okada, K. Akahane, Y. Iuchi, and M. Kawabe, gProbing
the Properties of Self-Organized InGaAs Quantum Dots on GaAs (311)B by
Conductive Atomic Force Microscope Tiph, MRS 2000 Fall Meeting, Boston,
Nov. 2000.

- Y. Okada, K. Akahane, Y. Iuchi, and M. Kawabe,
gSelf-Organized InGaAs Quantum Dots Studied By Using Conductive SPM
Tiph, 1st International Symposium on Nanoarchitectonics Using
Suprainteractions, Tsukuba, Nov. 2000.

- K. Akahane, H. Z. Xu, Y. Okada, and M. Kawabe, gSize and
Density Control of InGaAs Quantum Dotsh 1st International Symposium on
Nanoarchitectonics Using Suprainteractions, Tsukuba, Nov. 2000.

- (Invited) Y. Okada, gAFM nano-oxidation of GaAs and
application to nano-devicesh, Nanotechnology Forum V - Workshop on SPM
oxidation, Tsukuba, Oct. 2000.

- K. Akahane, S. Lan, H. Z. Song, Y. Okada, T. Takamasu, G.
Kido, and M. Kawabe, gThe Effects of Structure Ordering on Lateral
Coupling of Quantum Dots Grown on GaAs (311)B Studied by
Magnetoluminescenceh, 14th International Conference on High Magnetic
Fields in Semiconductor Physics, Matsue, Sept. 2000.

- K. Akahane, T. Kawamura, S. Lan, Y. Okada, and M. Kawabe,
gGrowth of InGaAs Quantum Dots on AlGaAs (311)B Surfaceh, 2000
International Symposium on Formation, Physics and Device Application of
Quantum Dot Structures, Sapporo, Sept. 2000.

- Y. Okamoto, K. Takahashi, Y. Okada, and M. Kawabe, gThe
Effect of Atomic Hydrogen on the III-Nitride Growth Dynamics in
RF-Molecular Beam Epitaxyh, International Workshop on Nitride
Semiconductors, Nagoya, Sept. 2000.

- Y. Okada, S. Seki, Y. Hagiwara, and M. Kawabe, gImproved
Dark Current Characteristics of GaAs/InGaAs Multi-Quantum Well Solar
Cells Fabricated by Atomic H-Assisted Molecular Beam Epitaxyh, 28th
IEEE Photovoltaic Specialists Conference, Anchorage, Sept. 2000.

- Y. Okamoto, K. Takahashi, H. Nakamura, Y. Okada, and M.
Kawabe, gThe Effects of Atomic Hydrogen on In Incorporation and
Ordering in InGaN grown by RF-MBEh, 3rd International Symp. on Blue
Laser and Light Emitting Diodes, Berlin, March 2000.

- K. Y. Jang, Y. Okada, and M. Kawabe, gEffect of Atomic
Hydrogen on GaAs Growth on GaAs(311)A Substrate in Molecular Beam
Epitaxyh, International Symposium on Surface Science for Micro- and
Nano-Device Fabrication, Tokyo, Nov. 1999.

- Y. Okada, Y. Iuchi, and M. Kawabe, gGaAs Oxide Patterns
Generated by SPM Tip-Induced Nano-Oxidation Technique Using Modulated
Tip Biash, 26th International Symposium on Compound Semiconductors,
Berlin, Aug. 1999.

- Y. Okada, Y. Suzuki, T. Kikuchi and M. Kawabe, gUse of
Multi-Quantum Wells for Photoabsorption Enhancement in Compound
Semiconductor Solar Cellsh, 1999 Electronic Materials Conference, Santa
Barbara, June 1999.

- K. Y. Jang, Y. Okada, and M. Kawabe, gEffects of hydrogen
in AlAs growth by atomic hydrogen-assisted molecular beam epitaxyh, MRS
1999 Spring Meeting, San Francisco, April 1999.

- Y. Okada, Y. Iuchi, M. Kawabe, and J. S. Harris, Jr.,
gGaAs/AlGaAs Oxide Tunnel Barriers Fabricated by Atomic Force
Microscope Tip-Induced Nano-Oxidation Techniqueh, 25th International
Symposium on Compound Semiconductors, Nara, Oct. 1998.

- Y. Okamoto, S. Hashiguchi, Y. Okada, and M. Kawabe,
gEffects of Atomic Hydrogen on the Growth of GaN grown by RF-MBEh, 2nd
International Symp. on Blue Laser and Light Emitting Diodes, Kisarazu,
Sept. 1998.

- Y. Okada, Y. Suzuki, M. Kawabe, N. Yui, and H. Kawanami,
gPhotovoltaic Properties of GaAs/InGaAs-Based Quantum Well Structures
Fabricated by Molecular Beam Epitaxy with Atomic Hydrogenh, 2nd World
Conference on Photovoltaic Solar Energy Conversion, Vienna, July 1998.

- S. Lan, K. Akahane, K. Y. Jang, T. Kawamura, Y. Okada, and
M. Kawabe, gTemperature and Excitation Dependence of Photoluminescence
from In0.4Ga0.6As Quantum Dots on GaAs (001) Substrates with Large
Surface Coverageh, 10th International Conference on InP and Related
Materials, Tsukuba, May 1998.

- (Invited) Y. Okada and J. S. Harris, Jr., gCurrent Control
in 2DEG Channel Using Scanning Probe Microscope Nano-Oxidation
Techniqueh, MRS 1998 Spring Meeting, San Francisco, April 1998.

- K. Akahane, T. Kawamura, S. Lan, Y. Okada, and M. Kawabe,
gControl of Size and Density of Self-organized Quantum Dots Grown on
GaAs (311)B by Atomic H-assisted Molecular Beam Epitaxyh, 3rd
International Symposium on Advanced Physical Fields, Tsukuba, Feb. 1998.

- Y. Okada, S. Amano, and M. Kawabe, gOn the Mechanism of
SPM Tip-Induced Nano-Oxidation Process of GaAsh, 3rd International
Symposium on Advanced Physical Fields, Tsukuba, Feb. 1998.

- (Invited) Y. Okada, gHigh-Quality GaAs-on-Si Grown by
Atomic Hydrogen-Assisted Molecular Beam Epitaxy for Photoelectronicsh,
International Topical Meeting on Photoelectronics, Beijing, Oct. 1997.

- K. Akahane, K. Okino, Y. Okada, and M. Kawabe,
gSelf-organized quantum dots grown on GaAs (311)B by atomic
hydrogen-assisted molecular beam epitaxyh, International Workshop on
Nano-Physics and Electronics, Tokyo, Sept. 1997.

- K. Y. Jang, Y. Okada, and M. Kawabe, gBand-gap energy
anomaly observed in AlGaAs grown by atomic hydrogen-assisted molecular
beam epitaxyh, International Workshop on Nano-Physics and Electronics,
Tokyo, Sept. 1997.

- Y. Okada, S. Amano, M. Kawabe, B. N. Shimbo, and J. S.
Harris, Jr., gAtomic Force Microscope Nanoscale Lithography For
Single-Electron Device Applicationsh, 24th International Symposium on
Compound Semiconductors, San Diego, Sept. 1997.

- Y. Okada, J. S. Harris, Jr., A. Sutoh, and M. Kawabe,
gGrowth of Abrupt GaAs/Ge Interfaces by Atomic Hydrogen-Assisted MBEh,
9th International Conference on Molecular Beam Epitaxy, Malibu, Aug.
1996.

- Y. Okada, J. S. Harris, Jr., and W. Gotz, gDeep Level
Defects in GaAs/Si Grown by Low Temperature Atomic H-assisted MBEh,
1996 Electronic Materials Conference, Santa Barbara, June 1996.

- B. N. Shimbo, J. S. Harris, Jr., Y. Okada, S. Komarov, and
B. J. Vartanian, gAtomic Force Microscope Chemically Induced Direct
Processing of GaAs and NiAlh, MRS 1996 Spring Meeting, San Francisco,
April 1996.

- Y. J. Chun, S. Nakajima, Y. Okada, and M. Kawabe, gUniform
Quantum Dots by Self-Organizing Process in Atomic Hydrogen-Assisted
MBEh, MRS 1995 Fall Meeting, Boston, Nov. 1995.

- Y. Okada, A. Sutoh, M. Kawabe, and J. S. Harris,
gGaAs-on-Ge Heteroepitaxy by Atomic Hydrogen-Assisted Molecular Beam
Epitaxyh, MRS 1995 Fall Meeting, Boston, Nov. 1995.

- Y. Okada, A. Kawabata, M. Kawabe, N. Yui, and H. Kawanami,
gGrowth of GaAs and AlGaAs on Si Substrates by Atomic Hydrogen-Assisted
MBE (H-MBE) for Solar Cell Applicationsh, IEEE 1st World Conference on
Photovoltaic Solar Energy Conversion, Hawaii, Dec. 1994.

- S. Ohta, Y. Okada, and M. Kawabe, gEffect of Atomic
Hydrogen Irradiation in Low-Temperature GaAs/Si Heteroepitaxyh, 8th
International Conference on Molecular Beam Epitaxy, Osaka, Aug. 1994.

- Y. J. Chun, Y. Okada, and M. Kawabe, gEffect of Atomic
Hydrogen on Highly Lattice-Mismatched Epitaxyh, 8th International
Conference on Molecular Beam Epitaxy, Osaka, Aug. 1994.

- Y. Okada, S. Ohta, H. Shimomura, H. Matsumoto, A.
Kawabata, and M. Kawabe, gAtomic Hydrogen-Assisted GaAs/Si
Heteroepitaxy for Solar Cell Applicationsh, 7th International
Photovoltaic Science and Engineering Conference, Nagoya, Nov. 1993.

- T. Sugaya, M. Kaneko, Y. Okada, and M. Kawabe, gOptical
Properties of GaAs Quantum Wire Structures by Hydrogen-Assisted
Molecular Beam Epitaxyh, International Symp. on Nanostructures
& Quantum Effects, Tsukuba, Nov. 1993.

- Y. Okada, S. Ohta, and M. Kawabe, gPhotoluminescence from
GaAs/AlGaAs Quantum Wells Grown by Low-Temperature MBE with Atomic
Hydrogen Irradiationh, 1993 International Conference on Solid State
Devices & Materials, Makuhari, Aug. 1993.

- Y. Okada, H. Shimomura, and M. Kawabe, gAtomic
Hydrogen-Assisted Molecular Beam Epitaxy of GaAs on Sih, 1993
Electronic Materials Conference, Santa Barbara, June 1993.

- T. Sugaya, Y. Okada, and M. Kawabe, gSelective Area Growth
of GaAs by Molecular Beam Epitaxyh, 19th International Symposium on
GaAs & Related Compounds, Karuizawa, Sept. 1992.

- Y. Okada, H. Shimomura, H. Matsumoto, S. Ohta, A.
Kawabata, and M. Kawabe, gElectrical Properties of Epitaxial GaAs Grown
by Low-Temperature MBE with Atomic Hydrogen Irradiationh, 19th
International Symposium on GaAs & Related Compounds, Karuizawa,
Sept. 1992.

- H. Shimomura, Y. Okada, and M. Kawabe, gReduction of
Dislocation Density of GaAs on Si(100) by Low-Temperature Growth and
Atomic Hydrogen Irradiationh, 1992 International Conference on Solid
State Devices & Materials, Tsukuba, Aug. 1992.

- Y. Okada, H. Shimomura, T. Sugaya, and M. Kawabe, gSurface
Cleaning of Si (100) by Atomic Hydrogen Irradiation and Its Structure
Studied by Scanning Tunneling Microscopeh, International Workshop on
Science and Technology for Surface Reaction Process, Tokyo, Jan. 1992.

- T. Sugaya, Y. Okada, and M. Kawabe, gInvestigation of
Growth Mechanism of GaAs by Molecular Beam Epitaxy with Atomic Hydrogen
Irradiationh, 1st International Symposium on Atomically Controlled
Surfaces & Interfaces, Tokyo, Nov. 1991.

- T. Ishibashi, Y. Okada, S. Yokoyama, and M. Kawabe,
gLayer-by-Layer Growth of Bi-Sr-Ca-Cu-O by Molecular Beam Epitaxyh,
1991 International Conf. on Solid State Devices & Materials,
Yokohama, Aug. 1991.

- T. Sugaya, H. Shimomura, Y. Okada, and M. Kawabe,
gSelective Growth of GaAs by Molecular Beam Epitaxy with Atomic
Hydrogen Irradiationh, 1991 International Conf. on Solid State Devices
& Materials, Yokohama, Aug. 1991.

- Y. Okada, H. Ajisawa, A. Moki, T. Sugaya, and M. Kawabe,
gLow Temperature Surface Preparation of Vicinal Si (100) for Epitaxial
Growth of GaAs on Sih, 1991 International Conf. on Solid State Devices
& Materials, Yokohama, Aug. 1991.

- (Invited) K. Tada, Y. Nakano, T. Ishikawa, Y. Okada, and
Y. C. Chan, gPrecise Control of the MBE System and its Application to
Thin Film Photonic Devicesh, C-MRS International 1990 Symposium,
Beijing, June 1990.

- Y. Okada and K. Tada, gGaAs/AlGaAs Reflection-Type Optical
Switch Using Heterojunction Bipolar Transistor Waveguide Structureh,
1990 International Topical Meeting on Photonic Switching, Kobe, April
1990.

- (Invited) K. Tada, Y. Okada, and T. Ishikawa,
Semiconductor Optical Modulator/Switch with Heterojunction Bipolar
Transistor Waveguide Structure, 2nd Regional Symposium on
Optoelectronics, Jakarta, Dec. 1989.

- Y. Okada, T. Ishikawa, Y. Nakano, and K. Tada,
gGaAs/AlGaAs Double-Graded Heterojunction Bipolar Transistor Prepared
by MBE with Precise Temperature Control Using Modern Control Theoryh,
1st International Meeting on Advanced Processing and Characterization
Technologies, Tokyo, Oct. 1989.

- Y. Okada, R. J. Simes, L. A. Coldren, J. L. Merz, and K.
Tada, GaAs/AlGaAs Double-Heterojunction Bipolar Transistor
Carrier-Injected Optical Intensity Modulatorh, 21st Conference on Solid
State Devices & Materials, Tokyo, Aug. 1989.

- Y. Okada, R. H. Yan, L. A. Coldren, J. L. Merz, and K.
Tada, gThe Effect of Band-Tailing on the Performance of GaAs/AlGaAs
Optical Modulators Operated by Free Carrier Injectionh, 1st IEEE/LEOS
Annual Meeting, Santa Clara, Nov. 1988.

- K. Tada and Y. Okada, gProposal of Bipolar Transistor Carrier-Injected Optical Modulators and Switchesh, 18th (International) Conference on Solid State Devices & Materials, Tokyo, Aug. 1986.