Hongjian Li, PhD
Assistant Project Scientist SSLEEC, Materials UCSB
Address: SSLEEC, Engineering II, Bldg. 503, UC Santa Barbara, CA 93106-5055
E-mail: hongjianli@ucsb.edu, Phone: (+1) 805-708-6766,
Homepage: https://sites.google.com/view/hongjianli.
RESEARCH INTERESTS:
MOCVD, III-nitrides, LEDs, LDs, Semipolar GaN. (MOCVD expert with hand-on runs>3000)
RESERCH SKILLS:
Ø MOCVD epitaxy growth (various kinds of MOCVD, Aixtron showerhead CCS, Horizontal G5, 2400, TNSC SR2000, Home-made two-flow reactor.)
Ø Materials characterization: XRD, SEM, Hall, PL, EL, AFM, SIMS, TEM etc.
Ø Fabrication: Lithography, etching ICP/RIE, PECVD, ALD, IBD, Ebeam, dicing, packaging.
ACHIEVEMENTS:
Ø World’s first CW semipolar (20-21) blue lasers hetero-epitaxially grown on sapphire. (2020)
Ø World’s first pulsed semipolar (11-22) blue lasers hetero-epitaxially grown on sapphire. (2019)
Ø World’s best MOCVD grown TJs µLEDs with lowest forward voltage and enhanced EQE using selective area growth (SAG) and n-GaN/n-InGaN TJs. (2020)
Ø Start-of-art efficient semipolar (11-22) and (20-21) InGaN long wavelength (green/yellow) LEDs grown on sapphire substrate. (2017-2019)
Ø First demonstration of efficient monolithic white semipolar LEDs directly grown on semipolar (20-21) bulk GaN and semipolar (20-21) GaN/sapphire substrate for Li-Fi. (2018-2019)
Ø First demonstration of m-plane nonpolar thin film LDs using ELOG technology and cleaving technology for the recycling costly m-plane bulk GaN. (2019)
Ø First demonstration of ELOG on m-plane GaN using with smooth surface. (2017)
Ø One of the worlds’ highest efficiency InGaN green LED on PSS: peak EQE and WPE>60% peak efficacy >300 lm/W, and EQE ~40% at 20 A/cm2. (2011-2014)
Professional experience:
Assistance Project Scientist SSLEEC, Materials at UCSB Oct. 2020-Now
UC Santa Barbara Oct. 2015-2020
Postdoctoral Researcher (working with Prof. S. P. DenBaars, Prof. S. Nakamura, and Prof. James S. Speck)
Ø Semipolar violet and blue LDs on foreign GaN/sapphire template
Ø Semipolar long wavelength LEDs on foreign GaN/sapphire template.
Ø MOCVD grown TJs for LEDs and µLEDs.
Ø MOCVD ELOG semipolar/nonpolar LDs/using cleaving technology for recycling substrate.
Ø Monolithic white semipolar LEDs with high polarization ratio and VLC application.
Ø MOCVD facility setup, epitaxy growth optimization, materials characterization for high efficiency LEDs under the sponsorship by UCSB- CREST Malaysia “GaN on GaN” project.
Northwestern University, US Oct. 2014- Oct. 2015
Postdoctoral Researcher (working with Prof. M. Razeghi)
Ø MOCVD grown Al(Ga)N materials and devices on sapphire/nano patterned Si substrate.
Educational background:
PhD Institute of Semiconductor, Chinese Academy of Science Jul. 2014
Thesis titled “Research on Quantum Efficiency Enhancement for 150 lm/W GaN Based
Light-Emitting Diodes”
B. A. Wuhan University, China, Jul. 2009
Major: Electronics Science and Technology
EWARDS AND HONORS:
Ø Outstanding Reviewer Awards for Nanotechnology 2017
Ø Outstanding Research Achievement Award in SSLEEC UCSB 2019.
Service on the Editorial Board of Professional Journals:
Ø Invited reviewer for JAP, ACS Photonics, Nanotechnology, IEEE Photonics, PTL, IEEE TED, J. Phys. D: Appl. Phys., AIP Advances, Applied Science et al.
Ø Invited topic editor for Crystal.
US/WORLD PATENTS (1 to 3 purchased by companies for commercialization):
1. Takeshi Kamikawa, Srinivas Gandrothula and Hongjian Li, METHOD OF REMOVING A SUBSTRATE WITH A CLEAVING TECHNIQUE. US2020/0203228A1/ WO2018204916Al. (Transfer to industries for commercialization interests)
2. Takeshi Kamikawa, Srinivas Gandrothula and Hongjian Li, Method of Removing a Substrate, US2020/0194615 A1/WO2019055936Al. (Transfer to industries for commercialization interests)
3. Takeshi Kamikawa, Srinivas Gandrothula and Hongjian Li, METHOD OF FABRICATING NON-POLAR AND SEMI-POLAR DEVICE USING EPITAXIAL LATERAL OVERGROWTH, UC 2018-427-1; G&C 30794.680-US-P1/WO2019191760A1. (Transfer to industries for commercialization interests)
4. James S. Speck, Michel Khoury, and Hongjian Li, Attorney Docket: 30794.723-US-P1, A METHOD TO FABRICATE HIGH ANGLE INCLINATION SEMIPOLAR SUBSTRATES SCALABLE TO LARGE SURFACE AREAS.
5. Michel Khoury, Hongjian Li, Haojun Zhang and Steven P. DenBaars, Attorney Docket: 30794.718-US-P1, A METHOD TO FABRICATE III-NITRIDE SEMIPOLAR AND NONPOLAR LASERS ON SCALABLE PATTERNED SAPPHIRE FOREIGN SUBSTRATES.
6. Michel Khoury, Daniel Cohen, Steven P. DenBaars and Hongjian Li, UC 2019-968-1; G&C 30794.0737USP1; Controlled Directional Light Extraction via High Aspect Ratio LED Strip Arrays.
7. Panpan Li, Hongjian Li, Mike, Iza, Shuji Nakamura, Steven P. DenBaars, US 2020-714-1 (G&C 30794.0774USP1) SIZE-INDEPENDENT FORWARD VOLTAGE IN MICRO-SIZE LIGHT-EMITTING DIODES WITH AN EPITAXIAL TUNNEL JUNCTION.
8. Panpan Li, Hongjian Li, Mike, Iza, Shuji Nakamura, Steven P. DenBaars, UC 2021-551 (G&C 30794.0782USP1) Activation of p-type layers of Tunnel junction.
JOURNAL PUBLICATIONS:
1. H. Li,* H. Zhang, J. Song, P. Li, S. Nakamura, S. P. DenBaars, “Toward heteroepitaxially grown semipolar GaN laser diodes under electrically-injected continuous-wave mode: from materials to lasers,” Submitted to Applied Physics Review, Under review, 2020.
2. H. Li,* H. Zhang, P. Li, J. Song, S. Nakamura, S. P. DenBaars, “Analysis of temperature-dependent electroluminescence properties of heteroepitaxial semipolar (20-21) blue laser diodes”, Submitted to Optics Express, Under review, 2020.
3. H. Zhang, P. Li, H. Li*, S. Nakamura, S. P. DenBaars, “Electrically driven, highly polarized monolithic white semipolar (20-21) InGaN micro-light-emitting diodes with surface plasmon coupled indium tin oxide gratings,” Accepted by Applied Physics Letter, 2020. (Corresponding author) (Editor’s Pick)
4. P. Li, H. Li*, H. Zhang, M. Iza, J. Speck, S. Nakamura, S. P. DenBaars, “Optimization of efficient metalorganic chemical vapor deposition grown TJs for InGaN light-emitting diodes: epitaxy design and light extraction simulation,” Submitted to Applied Surface Science, Under Review, 2020. (Corresponding author)
5. P. Li, H. Zhang, H. Li*, Y. Zhang. Y. Yao, N. Palmquist, M. Iza, J. Speck, S. Nakamura, S. P. DenBaars, “Metalorganic chemical vapor deposition grown n-InGaN/n-GaN tunnel junctions for micro-light-emitting diodes with very low forward voltage,” Semiconductor Science Technology, 35 125023, 2020. (Corresponding author)
6. P. Li, H. Li*, H. Zhang, M. Iza, , J. Speck, S. Nakamura, S. P. DenBaars, “Optimization of efficient metalorganic chemical vapor deposition grown TJs for InGaN light-emitting diodes: epitaxy design and light extraction simulation,” Submitted to Applied Surface Science, Under review, 2020. (Corresponding author)
7. H. Zhang, H. Li*, P. Li, J. Song, J. S. Speck, S. Nakamura, S. P. DenBaars, “Room-temperature continuous-wave electrically driven semipolar (20-21) blue laser diodes heteroepitaxially grown on sapphire substrate,” ACS Photonics 7, 1662, 2020. (Corresponding author). (Covered by Semiconductor Today: http://www.semiconductor-today.com/news_items/2020/aug/ucsb-060820.shtml)
8. H. Li, P. Li, H. Zhang, S. Nakamura, S. P. DenBaars, “Demonstration of efficient semipolar 410 nm violet laser diodes heteroepitaxially grown on high quality GaN/sapphire templates,” ACS Applied Electronics Materials, 2, 1874, 2020.
9. P. Li, H. Zhang, H. Li*, M. Iza, Y. Yao, M. S. Wong, N. Palmquist, J. S. Sspeck, S. Nakamura, S. P. DenBaars “Size-independent low voltage of InGaN micro-light-emitting diodes with epitaxial tunnel junctions using selective area growth by metalorganic chemical vapor deposition,” Optics Express, 28, 18707, 2020. (Corresponding author) (Featured by Semiconductor Today: http://www.semiconductor-today.com/news_items/2020/jul/ucsb-160720.shtml)
10. H. Li*, P. Li, H. Zhang, Y. Chow, M. S. Wong, S. Pinna, J. Klamkin, J. S. Sspeck, S. Nakamura, S. P. DenBaars, “Electrically driven, polarized, phosphor-free white semipolar (20-21) InGaN light-emitting diodes grown on semipolar bulk GaN substrate,” Optics Express, 28, 13569, 2020. (Covered by Semiconductor Today: http://www.semiconductor-today.com/news_items/2020/jun/ucsb-110620.shtml )
11. H. Li*, H. Zhang, P. Li, M. S Wong, Y. C. Chow, S. Pinna, J. Klamkin, P. Mierry, J. Speck, S. Nakamura, S. P DenBaars, “Development of efficient semipolar InGaN long wavelength light-emitting diodes and blue laser diodes grown on high quality semipolar GaN/sapphire template,” Journal of Physics: Photonics, 2, 18150, 2020.
12. M. Khoury, H. Li, B. Bonef, T. Mates, F. Wu, P. Li, M. S. Wong, H. Zhang, J. Song, J. Choi, J. S. Speck, S. Nakamura, and S. P. DenBaars “560 nm InGaN micro-LEDs on Low-defect Density and Scalable (20-21) Semipolar GaN on Patterned Sapphire Substrates,” Optics Express, 28, 18150, 2020.
13. M. Khoury, H. Li*, Panpan Li, Y. C. Chow, B. Bonef, H. Zhang, M. S. Wong, S. Pinna, J. Song, J. Choi, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Polarized monolithic white semipolar (20-21) InGaN light-emitting diodes grown on high quality (20-21) GaN/sapphire templates and its application to visible light communication,” Nano Energy, 67, 104236, 2020. (Corresponding author)
14. M. Khoury*, H. Li*, H. Zhang, B. Bonef, D. Cohen, F. Wu, M. Wong, P. DeMierry, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Demonstration of First Electrically Injected Semipolar Laser Diode on Low Defect Density Scalable Sapphire Substrates,” ACS Appl. Mat. Int. 11, 47106, 2019. (Equally contribution)
15. T. Kamikawa, S. Grandrothula, M. Araki, H. Li, V. Bonito Oliva, F. Wu, D. Cohen, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Realization of thin-film m-plane InGaN laser diode fabricated by epitaxial lateral overgrowth and mechanical separation from a reusable growth substrate,” Optics Express 27, 24717, 2019.
16. H. Li,* M. S Wong, M. Khoury, B. Bonef, H. Zhang, Y. C. Chow, P. Li, J. Kearns, A. A Taylor, P. De Mierry, Z. Hassan, S. Nakamura, S. P DenBaars, “Study of efficient semipolar (11-22) InGaN green micro-light-emitting diodes on high-quality (11-22) GaN/sapphire template”, Optics Express 27, 24154, 2019.
17. P. Li, Y. Zhao, H. Li,* Z. Li, Y. Zhang, J. Kang, M. Liang, Z. Liu, X. Yi, and G .Wang, Highly efficient InGaN green mini-size flipchip light-emitting diodes with AlGaN insertion layer, Nanotechnology 30, 095203, 2019. (Corresponding author)
18. P. Li, Y. Zhao, H. Li,* J. Che, Z. Zhang, Z. Li, Y. Zhang, L. Wang, M. Liang, X. Yi, and G. Wang, “Very high external quantum efficiency and wall-plug efficiency 527 nm InGaN green LEDs by MOCVD”, Optics Express 26 (25), 33108-33115, 2018. (Corresponding author)
19. M. Khoury, H. Li,* B. Bonef, L. Y. Kuritzky, A. J. Mughal, S. Nakamura, J. S. Speck, and S. P. DenBaars, “Semipolar GaN templates on sapphire: 432 nm InGaN light-emitting diodes and light extraction simulations”, Appl. Phys. Express 11, 036501, 2018. (Equally contribution)
20. P. Li, Y. Zhao, X. Yi, H. Li*, “Effects of a Reduced Effective Active Region Volume on Wavelength-Dependent Efficiency Droop of InGaN-Based Light-Emitting Diodes”, Applied Sciences 8, 2138, 2018. (Corresponding author)
21. Y. Zhang,* H. Li,* L. Liu, P. Li, L. Wang, X. Yi, G. Wang, “UV-C whispering-gallery modes in AlN microdisks with AlGaN-based multiple quantum wells on Si substrate,” Journal of Nanophotonics 12, 043502, 2018. (Equally contribution)
22. I. Demir, H. Li, Y. Robin, R. McClintock, S. Elagoz, M. Razeghi. “Sandwich method to grow high quality AlN by MOCVD,” J. Phys. D: Appl. Phys. 51, 085104, 2018.
23. P. Li, B. Bonef, M. Khoury, G. Lheureux, H. Li,* J. Kang, S. Nakamura and S. P. DenBaars, “Carrier dynamics of two distinct localized centers in 530 nm InGaN green light-emitting diodes”, Superlattices and Microstructures, 113, 684, 2018. (Corresponding author)
24. H. Li,* M. Khoury, B. Bonef, A. I. Alhassan, A. J. Mughal, E. Azimah, M. E.A. Samsudin, P. De Mierry, S. Nakamura, J. S. Speck, and S. P. DenBaars, “Efficient Semipolar (11-22) 550 nm Yellow/Green InGaN Light-Emitting Diodes on Low Defect Density (11–22) GaN/Sapphire Templates”, ACS Appl. Mater. Interfaces, 9, 36417, 2017.
25. M. Khoury, H. Li, L. Y. Kuritzky, A. J. Mughal, P. DeMierry, S. Nakamura, J. S. Speck S. P. DenBaars, “444 nm InGaN light emitting diodes on low-defect-density GaN templates on patterned sapphire”, Appl. Phys. Express 10, 106501, 2017. (Equally contribution)
26. Y. Zhang, H. Li, P. Li, A. Dehzangi, L. Wang, X. Yi, G. Wang, “Optically-pumped single-mode deep-ultraviolet microdisk lasers with AlGaN-based multiple quantum wells on Si substrate”, IEEE Photonics J. 9, 2400508, 2017. (Equally contribution)
27. L. Wang, Z. Liu, Z. Li, Y. Zhang, H. Li, X. Yi, J. Wang, G. Wang, J. Li, “Nanostructure nitride light emitting diodes via the Talbot effect using improved colloidal photolithography”, Nanoscale 9, 7021, 2017.
28. J. Kang, V.Q. Dang, H. Li, S. Moon, P. Li, Y. Kim, C. Kim, J. Choi, H. Choi, Z. Liu, “Broadband light-absorption InGaN photoanode assisted by imprint patterning and ZnO nanowire growth for energy conversion”, Nanotechnology 28, 045401, 2016.
29. J. Kang, V. Dang, H. Li, S. Moon, P. Li, Y. Kim, C. Kim, H. Choi, Z. Liu, H. Lee, “InGaN-based photoanode with ZnO nanowires for water splitting”, Nano convergence 3, 34, 2016.
30. Z-H. Zhang, Y. Zhang, H. Li, S. Xu, C. Geng, W Bi, “On the Importance of the Polarity for GaN/InGaN Last Quantum Barriers in III-Nitride-Based Light-Emitting Diodes”, IEEE Photonics J. 8, 1, 2016.
31. L. Wang, Z. Liu, X. Yi, Y. Zhang, H. Li, J. Li, G. Wang, “Analysis of symmetry breaking configurations in metal nanocavities: Identification of resonances for generating high-order magnetic modes and multiple tunable magnetic-electric Fano resonances”, J. Appl. Phys. 119, 173106, 2016.
32. H. Li, P. Li, J. Kang, J. Ding, J. Ma, Y. Zhang, X. Yi, G. Wang, “Broadband full-color monolithic InGaN light-emitting diodes by self-assembled InGaN quantum dots”, Scientific Reports 6, 35217, 2016.
33. P. Li, H. Li,* Y. Zhao, J. Kang, Z. Li, Z Liu, X. Yi, J. Li, G Wang, “Excellent ESD Resistance Property of InGaN LEDs With Enhanced Internal Capacitance”, IEEE Photonics Technology Letters, 27, 2004, 2015. (Corresponding author)
34. P. Li, H. Li,* Z. Li, J. Kang, X. Yi, J. Li, G. Wang, “Strong carrier localization effect in carrier dynamics of 585 nm InGaN amber light-emitting diodes”, J. Appl. Phys. 117, 073101, 2015. (Corresponding author)
35. P. Li, H. Li,* L. Wang, X. Yi, G. Wang, “High Quantum Efficiency and Low Droop of 400-nm InGaN Near-ultraviolet light-emitting diodes through suppressed leakage current”, IEEE J. Quantum Electronics 51, 1, 2015. (Corresponding author)
36. Z. Li, J. Kang, B. Wang, H. Li, Y. Hsiang Weng, YC Lee, Z. Liu, X. Yi, G. Wang, “Two distinct carrier localization in green light-emitting diodes with InGaN/GaN multiple quantum wells”, J. Appl. Phys. 115, 083112, 2014.
37. J. Kang, Z. Li, Z. Liu, H. Li, Y. Zhao, Y. Tian, P. Ma, X. Yi, G. Wang, “Investigation of the wet-etching mechanism of Ga-polar AlGaN/GaN micro-pillars,” Journal of Crystal Growth, 386, 175, 2014.
38. H. Li,* P. Li, J. Kang, Z. Li, Z. Li, J. Li, X. Yi, G. Wang, “Phosphor-free, color-tunable monolithic InGaN light-emitting diodes”, Appl. Phys. Express 6, 102103, 2013. (Covered by Semiconductor Today: http://www.semiconductor-today.com/news_items/2013/NOV/CAS_041113.shtml )
39. J. Kang, Z. Li, H. Li, Z. Liu, P. Ma, X. Yi, G. Wang, “Optimal width of quantum well for reversed polarization blue InGaN light-emitting diodes”, AIP Advances 3, 072121, 2013.
40. J. Kang, H. Li, Z. Li, Z. Liu, P. Ma, X. Yi, G. Wang, “Enhancing the performance of green GaN-based light-emitting diodes with graded superlattice AlGaN/GaN inserting layer”, Appl. Phys. Lett. 103, 102104, 2013.
41. H. Li,* P. Li, J. Kang, Z. Li, Y. Zhang, M. Liang, Z. Li, J. Li, X. Yi, G. Wang, “Analysis model for efficiency droop of InGaN light-emitting diodes based on reduced effective volume of active region by carrier localization”, Appl. Phys. Express 6, 092101, 2013.
42. H. Li,* P. Li, J. Kang, Z. Li, Y. Zhang, Z. Li, J. Li, X. Yi, J. Li, G. Wang, “Quantum efficiency enhancement of 530 nm InGaN green light-emitting diodes with shallow quantum well”, Appl. Phys. Express 6, 052102, 2013. (Covered by Semiconductor Today: http://www.semiconductor-today.com/news_items/2013/MAY/GREENLEDS_060513.html)
43. H. Li,* J. Kang, P. Li, J. Ma, H. Wang, M. Liang, Z. Li, J. Li, X. Yi, G. Wang, “Enhanced performance of GaN based light-emitting diodes with a low temperature p-GaN hole injection layer”, Appl. Phys. Lett. 102, 011105, 2013.
44. J. Kang, Z. Li, H. Li, Z. Liu, X. Li, X. Yi, P. Ma, H. Zhu, G. Wang, “Pyramid Array InGaN/GaN Core–Shell Light Emitting Diodes with Homogeneous Multilayer Graphene Electrodes”, Appl. Phys. Express 6, 072102, 2013. (Covered by Semiconductor Today: http://www.semiconductor-today.com/news_items/2013/JUL/CAS_170713.html