Geun Ho Ahn (안근호)

I am a third year PhD student at Stanford University in Electrical Engineering advised by Professor Jelena Vuckovic, supported by STMicroelectronics Stanford Graduate Fellowship. My current research interests lie at the intersection of integrated photonics, machine learning, optimization and optical materials, specifically towards integrated optical systems, such as AR/VR, LiDAR, and on-chip data communications.

Previously, I received my B.S. degree in EECS at University of California, Berkeley, where I was advised by Professor Ali Javey on novel optoelectronics and optical material synthesis.

I was born in Ulsan, South Korea, and was raised in Prague, Czechia.

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  • Oral Presentation at Conference on Lasers and Electro-Optics (CLEO) in March, 2020.
  • Our work on on-chip Silicon LiDAR is published on Nature Photonics in 2020.
  • Passed Stanford EE qualifying exam in 2020.
  • Our work on synthetic monolayer with high quantum yield is published on Science Advances in 2019.
  • Started PhD at Stanford University in Fall 2018.
Selected Publications
sym Synthetic WSe2 monolayers with high photoluminescence quantum yield
Hyungjin Kim*, Geun Ho Ahn*, Joy Cho, Matin Amani, James P. Mastandre, Catherine K. Groschner, Der-Hsien Lien, Yingbo Zhao, Joel W. Ager III, Mary C. Scott, Daryl C. Chrzan, & Ali Javey.
Science Advances, 2019.

Large scale symthetic monolayer films can demonstrate much higher quantum yield than mechanically exfoliated counterparts, if grown properly.

sym Strain-engineered growth of two-dimensional materials
Geun Ho Ahn*, Matin Amani*, Haider Rasool, Der-Hsien Lien, James P. Mastandrea, Joel W. Ager III, Madan Dubey, Daryl C. Chrzan, Andrew M. Minor & Ali Javey.
Nature Communications, 2017.

Highlighted by U.S. Department of Energy / Lawrence Berkeley Laboratory /

Engineering the intrinsic van der waal interaction between the electronic substrate and two dimentional materials for built-in strain tunability via large scale growth.

Full Publication List
  1. K. Y. Yang, J. Skarda, M. Cotrufo, A. Dutt, G. H. Ahn, M. Sawaby, D. Vercruysse, A. Arbabian, S. Fan, A. Alu, J. Vuckovic. "Inverse-designed non-reciprocal pulse router for chip-based LiDAR", Nature Photonics 14 (6), 369-374, 2020.
  2. A. J. Goodman, D.-H. Lien, G. H. Ahn, L.L. Spiegel, M. Amani, A.P. Willard, A. Javey, W. A. Tisdale. "Substrate-Dependent Exciton Diffusion and Annihilation in Chemically Treated MoS2 and WS2", The Journal of Physical Chemistry C, 2020.
  3. D. M. Lukin, C. Dory, M. A. Guidry, K. Y. Yang, S. D. Mishra, R. Trivedi, M. Radulaski, S. Sun, D. Vercruysse, G. H. Ahn, J. Vuckovic "4H-silicon-carbide-on- insulator for integrated quantum and nonlinear photonics", Nature Photonic 14 (5), 330-334, 2020
  4. A. Y. Piggott, E. Y. Ma, L. Su, G. H. Ahn, N. V. Sapra, D. Vercruysse, A. M. Netherton, A. Khope, J. E. Bowers, J. Vuckovic "Inverse-designed photonics for semiconductor foundries", ACS Photonics 7 (3), 569-575, 2020
  5. P. Zhao, R. Wang, D.-H. Lien, Y. Zhao, H. Kim, J. Cho, G. H. Ahn, A. Javey, "Scanning probe lithography patterning of monolayer semiconductors and application in quantifying edge recombination", Advanced Materials, 31 (48), 1900136, 2019
  6. J. Pak, I. Lee, K. Cho, J. K. Kim, H. Jeong, W. T. Hwang, G. H. Ahn, K. Kang, W. J. Yu, A. Javey, S. Chung, T. Lee, "Intrinsic optoelectronic Characteristics of MoS2 Phototransistors via Fully Transparent van der Waals Heterostructure", ACS Nano, 13 (8), 9638-9646, 2019
  7. K. Han, G. H. Ahn, J. Cho, D.-H. Lien, M. Amani, S. B. Desai, G. Zhang, H. Kim, N. Gupta, A. Javey, M. C. Wu, "Bright electroluminescence in ambient conditions from WSe2 p-n diodes using pulsed injection", Applied Physics Letters, 115, 011103, 2019.
  8. H. Kim*, G. H. Ahn*, J. Cho, M. Amani, J. P. Mastandrea, C. K. Groschner, D.-H. Lien, Y.Zhao, J. W. Ager, M. C. Scott, D. C. Chrzan, A. Javey, "Synthetic WSe2 monolayers with high photoluminescence quantum yield”, Science Advances, 5, eaau4728, 2019. [*] These authors contribute equally to this work
  9. D. Yoo, Y. Kim, M. Min, G. H. Ahn, D.-H. Lien, J. Jang, H. Jeong, Y. Song, S. Chung, A. Javey, T. Lee, "Highly reliable superhydrophobic protection for organic field-effect transistors by fluoroalkylsilane-coated TiO2 nanoparticles", ACS Nano, 12, 11062-11069, 2018.
  10. J. Bullock, M. Amani, J. Cho, Y.-Z. Chen, G. H. Ahn, V. Adinolfi, V. R. Shrestha, Y. Gao, K. B. Crozier, Y.-L. Chueh, A. Javey, "Polarization-resolved black phosphorus/molybdenum disulfide mid-wave infrared photodiodes with high detectivity at room temperature", Nature Photonics, 12, 601–607, 2018.
  11. D.-H. Lien, M. Amani, S. B. Desai, G. H. Ahn, K. Han, J.-H. He, J. W. Ager III, M. C. Wu, A. Javey, "Large-area and bright pulsed electroluminescence in monolayer semiconductor", Nature Communications, 9, 1229, 2018.
  12. M. Amani, E. Regan, J. Bullock, G. H. Ahn, A. Javey, "Mid-Wave Infrared Photoconductors Based on Black Phosphorous-Arsenic Alloys", ACS Nano, 11 (11), 11724–11731, 2017.
  13. G. H. Ahn*, M. Amani*, H. Rasool, D.-H. Lien, J. P. Mastandrea, J. W. Ager, M. Dubey, D. C. Chrzan, A. M. Minor, A. Javey, "Strain-engineered growth of two-dimensional materials”, Nature Communications, 8, 608, 2017. [*] These authors contribute equally to this work.
  14. P. Zhao, M. Amani, D.-H. Lien, G. H. Ahn, D. Kiriya, J. P. Mastandrea, J. W. Ager III, E. Yablonovitch, D. C. Chrzan, A. Javey, "Measuring the Edge Recombination Velocity of Monolayer Semiconductors", Nano Letters, 17, 5356–5360, 2017
  15. T.-Y. Kim, Y. Song, K. Cho, M. Amani, G. H. Ahn, J. Pak, J.-K. Kim, S. Chung, A. Javey, T. Lee, "Analysis on the interface characteristics of CVD-grown monolayer MoS2 by noise measurements”, Nanotechnology, 28 (14), 145702, 2017.
  16. J. Pak, M. Min, K. Cho, D.-H. Lien, G. H. Ahn, J. Jang, D. Yoo, S. Chung, A. Javey, and T. Lee, "Improved photoswitching response times of MoS2 field-effect transistors by stacking p-type copper phthalocyanine layer", Appl. Phys. Lett., 109, 183502, 2016.
  17. S. B. Desai, S. R. Madhvapathy, A. B. Sachid, J. P. Llinas, Q. Wang, G. H. Ahn, G. Pitner, M. J. Kim, J. Bokor, C. Hu, H.-S. P. Wong, A. Javey, "MoS2 transistors with 1-nanometer gate lengths", Science, 354, 99-102, 2016.
  18. Y. Song, H. Jeong, S. Chung, G. H. Ahn, T.-Y. Kim, J. Jang, D. Yoo, H. Jeong, A. Javey, T. Lee, "Origin of multi-level switching and telegraphic noise in organic nanocomposite memory devices", Scientific Reports, 6, 33967, 2016.
  19. M. Amani, R. A. Burke, X. Ji, P. Zhao, D.-H. Lien, P. Taheri, G. H. Ahn, D. Kirya, J. W. Ager III, E. Yablonovitch, J. Kong, M. Dubey, A. Javey, "High Luminescence Efficiency in MoS2 Grown by Chemical Vapor Deposition", ACS Nano, 10, 6535– 6541, 2016.
  20. M. Tosun, L. Chan, M. Amani, T. Roy, G. H. Ahn, P. Taheri, C. Carraro, J. Ager, R. Maboudian, A. Javey, "Air Stable n-Doping of WSe2 by Anion Vacancy Formation with Mild Plasma Treatment", ACS Nano, 10, 6853–6860, 2016.
  21. M. Amani, P. Taheri, R. Addou, G. H. Ahn, D. Kiriya, D.-H. Lien, J. W. Ager III, R. M. Wallace, A. Javey, "Recombination Kinetics and Effects of Superacid Treatment in Sulfur- and Selenium-Based Transition Metal Dichalcogenides", Nano Letters, 16 (4), 2786–2791, 2016.
  22. T.-Y. Kim, M. Amani, G. H. Ahn, Y. Song, A. Javey, S. Chung, T. Lee, "Electrical Properties of Synthesized Large-Area MoS2 Field-Effect Transistors Fabricated with Inkjet-Printed Contacts", ACS Nano, 10, 2819 (2016).
  23. T. Roy, M. Tosun, M. Hettick, G. H. Ahn, C. Hu, and A. Javey, "2D-2D tunneling field-effect transistors using WSe2/SnSe2 heterostructures", Appl. Phys. Lett., 108, 083111, 2016.

Reviewer in ACS Photonics

EE 340: Optical Micro- and Nano-Cavities : Grader, Spring 2020

EE 222: Applied Quantum Mechanics I : Grader, Fall 2019

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