Geun Ho Ahn (안근호)
I am a postdoctoral researcher at Stanford University, specializing in integrated photonics, material sciences, and computational optimization to develop innovative photonic-electronic systems for optical interconnects, metrology, and quantum science.
I earned my Ph.D. in Electrical Engineering from Stanford University, where I worked with Professor Jelena Vuckovic as a SGF fellow and FMA fellow on integrated photonics system through heterogeneous integration and photonic inverse design.
I completed my B.S. in EECS from UC Berkeley, where I worked with Professor Ali Javey as a Haas Scholar on optoelectronics and optical material synthesis.
I have served as a teaching assistant/co-lecturer in EE and MSE Departments at Stanford University. For this, I was awarded James F. Gibbons Award, (EE departmental teaching award).
I was born in Ulsan, South Korea, and I spent my formative years in Prague, Czechia.
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Unified laser stabilization and isolation on a silicon chip
Alexander D. White*, Geun Ho Ahn*, Richard Luhtaru, Joel Guo, Theodore J. Morin, Abhi Saxena, Lin Chang, Arka Majumdar, Kasper Van Gasse, John E. Bowers, Jelena Vučković. [*] equal contributions.
arXiv, 2024.
A fully passive and unified approach to simultaneously isolate and stabilize on-chip laser systems through nonlinear integrated photonics.
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Platform-agnostic waveguide integration of high-speed photodetectors with evaporated tellurium thin films
Geun Ho Ahn*, Alexander D. White*, Hyungjin Kim*, Naoki Higashitarumizu, Felix M. Mayor, Jason F. Herrmann, Wentao Jiang, Kevin K. S. Multani, Amir H. Safavi-Naeini, Ali Javey, Jelena Vučković. [*] equal contributions.
Optica, 2023.
A simple lithographically defined, thermal evaporation of semiconducting tellurium thin film allows for high-speed integrated photodetectors (> 40GHz) on novel photonic platforms that otherwise lack electrical readouts without any complex fabrication processes.
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Integrated Passive Nonlinear Optical Isolators
Alexander D. White*, Geun Ho Ahn*, Kasper Van Gasse, Ki Youl Yang, Lin Chang, John E. Bowers, Jelena Vučković. [*] equal contributions.
Nature Photonics, 2022.
Highlighted by Stanford News
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Stanford Engineering
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Phys.org
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optics.org
Integrated optical isolator without any external drive can be made to protect on-chip laser systems using optical nonlinear Kerr-effect in CMOS-ready thin film silicon nitride platforms
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Photonic Inverse Design of On-Chip Microresonators
Geun Ho Ahn, Ki Youl Yang, Rahul Trivedi, Alexander D. White, Logan Su, Jinhie Skarda, Jelena Vučković
ACS Photonics, 2022.
Computational optimization aided design approach can generalize on-chip resonator design processes to enable new functionalities such as wide dispersion engineering, high optical quality factor, and more.
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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 synthetic monolayer films can demonstrate much higher quantum yield than mechanically exfoliated counterparts, if grown properly.
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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
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Lawrence Berkeley Laboratory
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phys.org
Engineering the intrinsic van der waal interaction between the electronic substrate and two dimentional materials for built-in strain tunability via large scale growth.
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Full Publication List
- G. H. Ahn*, A. D. White*, H. Kim*, N. Higashitarumizu, F. M. Mayor, J. F. Herrmann, W. Jiang, K. KS Multani, A. H. Safavi-Naeini, A. Javey, J. Vuckovic. "Platform-agnostic waveguide integration of high-speed photodetectors with evaporated tellurium thin films", arXiv:2209.04034. 2022. [*] These authors contribute equally to this work
- A. D. White*, G. H. Ahn*, K. V. Gasse, K. Y. Yang, L. Chang, J. E. Bowers, J. Vuckovic. "Integrated Passive Nonlinear Optical Isolators", Nature Photonics in press [*] These authors contribute equally to this work
- H. Batiz, J. Guo, G. H. Ahn, H. Kim, A. Javey, J. W. Ager, D. C. Chrzan"Theory of liquid-mediated strain release in two-dimensional materials", Physical Review Materials 6 (5), 054005, 2022.
- G. H. Ahn, K. Y. Yang, R. Trivedi, A. D. White, L. Su, J. Skarda, J. Vuckovic. "Photonic Inverse Design of On-Chip Microresonators ", ACS Photonics 2022.
- J. Skarda, G. H. Ahn, R. Trivedi, T. Wu, S. Mitra, J. Vuckovic. "Inverse-Design for High-Performance Computing Photonics in Silicon Photonics for High-Performance Computing and Beyond", CRC Press. 159-176, 2021.
- 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.
- 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.
- 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
- 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
- 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
- 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
- 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.
- 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
- 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.
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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.
- 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.
- 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.
- 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.
- 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
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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).
- 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.
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