Invited Works

1. High Performance Normally-off GaN-based HEMTs achieved with Recessed and Regrown Channel Structures (invited talk)

 Joel T. Asubar, Shogo Maeda,  Ali Baratov, Suguru Terai, Takahiro Igarashi, Kishi Sekiyama, Masaaki Kuzuhara, and Akio Yamamoto

11th Asia-Pacific Workshop on Widegap Semiconductor (APWS 2024), Busan, South Korea, Oct. 14, 2024

2. Breaking the trade-off of drain current and threshold voltage in Normally-off GaN-based MIS-HEMTs by state-of-the-art regrowth technology  (invited talk)

Joel T. Asubar, Shinsaku Kawabata, Shogo Maeda, Ali Baratov, Suguru Terai, Takahiro Igarashi, Kishi Sekiyama, Masaaki Kuzuhara, and Akio Yamamoto

第７回有機・無機エレクトロニクスシンポジウム, 福井大学、2024年06月08日

(7th Organic and Inorganic Electronics Symposium: O&I Symposium, University of Fukui, June 8, 2024)

3. MOVPE growth of AlGaN on RIE-treated GaN surfaces and its application to AlGaN/GaN electron devices (invited talk)

 Akio Yamamoto, Ali Baratov,  Masaaki Kuzuhara, and Joel T. Asubar

2023 IEEE International Meeting for Future of Electron Devices ,Kansai (IMFEDK 2019), Kyoto, Nov 16, 2023

4. Innovation Technologies for Highly Safe and Energy-efficient GaN Devices (invited talk)

 Joel T. Asubar

 IEEE R10 Webinar Series – “IEEE R10Talk” April 22 2023

5. Mist chemical vapor deposited-gate insulators for GaN-based MIS devices applications(invited talk)

 Zenji Yatabe, Yusui Nakamura, Joel T. Asubar

 2022 IEEE IMFEDK Tech. Dig. doi: 10.1109/IMFEDK56875.2022.9975434

6. Recent progress in buffer-free GaN-on-SiC HEMT epitaxial heterostructures for microwave and power devices

(invited talk)

 D.-Y. Chen, B. Hult, F. Wach, M. Smith, J. Pomeroy, M. Uren, M. Kuball, J. Lu, M. Dahlqvist, K.-S. Wen, M. Lorenzini, J. Rosen, M. Thorsell,     L. Hultman, E. Zanoni,  J. T. Asubar, M. Kuzuhara, A. Pantellini, M. Natali, L. Latessa, C. Lanzieri,  J. Grünenpütt, D. Sommer, J. Splettstößer,  H. Stieglauer, H. Blanck,  O. Hilt, S. Shevchenko, O. Bengtsson, H.-J. Würfl, N. Rorsman J.-T. Chen

Presented at the  GaN Marathon 2022 , Venice , Italy, June 21, 2022

7. Enhancement-Mode AlGaN/GaN MIS-HEMTs With High VTH and High IDmax Using Recessed-Structure With Regrown AlGaN Barrier (invited talk)

  J. T. Asubar, S. Kawabata, H. Tokuda, A. Yamamoto, and M. Kuzuhara

  Presented at the  21st Kansai Colloquium, Electron Devices Workshop (online), Kyoto, Japan, Sept. 28, 2021

8.  Controlling surface-interface states in GaN-based transistors- Surface model, insulated gate, and surface passivation (invited tutorial)

J. T. Asubar, Z. Yatabe, D. Gregusova and T. Hashizume

Journal of Applied Physics 129 (2021), 121102

9. Recent progress in Normally-off GaN-based transistors (invited talk)

  J. T. Asubar, S. Kawabata, H. Tokuda, A. Yamamoto, and M. Kuzuhara

  Presented at the Recent Topics on GaN Semiconductor Devices in Osaka University, Osaka, Japan, July 5, 2019

10. Effective Suppression of Current Collapse in AlGaN/GaN HEMTs (invited talk)

  J. T. Asubar, H. Tokuda, and M. Kuzuhara

  Presented at the 35th Samahang Pisika ng Pilipinas Physics Conference, Cebu, Philippines, June 7-10, 2017

11.  Effect of Passivation on Breakdown voltage and dynamic on-resistance in AlGaN/GaN HEMTs (invited talk)

   M. Kuzuhara, J. T. Asubar, H. Tokuda

   Presented at the 2016 European Material Research Society, Warsaw, Poland, Sept. 19-26, 2016

12. Improved performance in MMC AlGaN/GaN HEMTs (invited lecture)

  J. T. Asubar, H. Tokuda, M, Kuzuhara, Z. Yatabe, K. Nishiguchi, and T. Hashizume

  Kumamoto University, Japan, October 3, 2016

13. Pushing the GaN HEMT towards its theoretical limit (invited article)

  J. T. Asubar, J. Ng, H. Tokuda, M, Kuzuhara

  Compound Semiconductor Magazine 22 (7) (2016) 21.

14.   Improved linearity, stability, and thermal performance of multi-mesa-channel AlGaN/GaN HEMTs (invited talk)

  J. T. Asubar, H. Tokuda, M, Kuzuhara, Z. Yatabe, K. Nishiguchi, and T. Hashizume

  Presented at the 34th Samahang Pisika ng Pilipinas Physics Conference, University of the Philippines Visayas, Iloilo, Philippines, August 18-21, 2016

15.   Insulated gate and surface passivation structures for GaN-based power transistors (invited paper)

  Z. Yatabe, J. T. Asubar, and T. Hashizume

  Journal of Physics D: Applied Physics 49 (39), 393001

16.  AlGaN/GaN HEMT Technology for High-Voltage and Low On-Resistance Operation (invited paper)

  M. Kuzuhara, J. T. Asubar, H. Tokuda

  Japanese Journal of Applied Physics 55 (7) (2016) 070101

17.   GaN-based Power Devices (invited talk)

  M. Kuzuhara, J. T. Asubar, and H. Tokuda 

  Presented at the 5th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies, Niigata, Japan, June  

  16- 19, 2015

18.  Reduced Current Collapse in High Pressure Water Vapor Annealed AlGaN/GaN HEMTs (invited lecture)

  J. T. Asubar, Y. Kobayashi, K. Yoshitsugu, Z. Yatabe, H. Tokuda, M. Horita, Y. Uraoka, T. Hashizume, and M. Kuzuhara

  Nara Institute of Technology, Japan, May 29, 2015

19.  Status and Prospects for GaN-based Power Transistors (invited talk)

  M. Kuzuhara, J. T. Asubar, and H. Tokuda

  Presented at the 1st  Lecture meeting of Advanced Power Semiconductor Subcommittee (Senshin pawaa handoutai bunka-kai dai-1 kai in Japanese),    Nagoya, Japan, November 19-20, 2014

20.  MBE-grown ZnSnAs2 Epitaxial Films: A Ferromagnetic Semiconductor Host Prospect (invited book chapter)

  J. T. Asubar, H. Oomae, and N. Uchitomi

  Book chapter in “Chalcopyrite: Chemical Composition, Occurrence and Uses”, (2014) pp. 51-94

  Nova Science Publishers, Inc., (Hauppauge) New York, ISBN: 978-1-63321-189-6

21. Current Stability in Multi-Mesa-Channel AlGaN/GaN HEMTs (invited paper)

  K. Ohi, J. T. Asubar, K. Nishiguchi, and T. Hashizume

  IEEE Transactions on Electron Devices, 60, (2013), 2997

22. GaN Transistors for Next-generation Power Conversion System (invited Talk)

  J. T. Asubar and T. Hashizume

  Presented at the 1st International Symposium on Technology and Sustainability,

  KMITL, Bangkok, Thailand, January 26-29, 2012