Dr. Ryou Research Group

Semiconductor Materials and Applications

 

Notable Papers

 

·        "Flexible single-crystalline GaN substrate by direct deposition of III-N thin films on polycrystalline metal tape," J. Mater. Chem. C 9 (7), 2243−2251 (2021). [Featured front-cover article in issue 7 of volume 9 (February, 2021)]

 

·        "Highly-sensitive skin-attachable self-powered eye-movement sensor using flexible non-hazardous piezoelectric thin film," Adv. Funct. Mater. 31 (8), 2008242-1−11 (2020). (IF: 16.836)

 

·         "Modulation of the 2-dimensional electron gas channel in flexible AlGaN/GaN high-electron-mobility transistors by mechanical bending," Appl. Phys. Lett. 116 (12), 123501-1–5 (2020). [Featured editor’s pick article in issue 12 of volume 116 (March, 2020)]

 

·         "High durable, biocompatible and flexible piezoelectric pulse sensor using III-N thin film," Adv. Funct. Mater. 29 (37), 1903162-1–10 (2019). [Featured back-cover article in issue 37 of volume 29 (September, 2019)] (IF = 15.621)

 

·         "Polarization modulation effect of BeO on AlGaN/GaN high-electron-mobility transistors," Appl. Phys. Lett. 115 (10), 103502-1–5 (2019). [Featured editor’s pick article in issue 10 of volume 115 (September, 2019)]

 

·         (Invited review paper) "Thermal management and characterization of high-power wide-bandgap semiconductor electronic and photonic devices in automotive applications," J. Electron. Packaging 141, 020801-1‒17 (2019).

 

·         "Flexible GaAs solar cells on roll-to-roll processed epitaxial Ge films on metal foils: a route towards low-cost and high-performance III-V photovoltaics," Energy Environ. Sci. 12, 756‒766 (2019). (IF = 33.250)

 

·         "Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using flexible III-nitride thin-film-based piezoelectric generator," Nano Energy 57, 670‒679 (2019). (IF = 15.548)

 

·         "High-efficiency flexible III-V thin-film photovoltaic solar cells based on single-crystal-like thin-film directly grown on metallic tapes," Prog. Photovoltaics: Res. Appl. 27 (1), 30‒36 (2019). [Featured cover article in issue 1 of volume 27 (January, 2019)]

 

·         "Improved light output power of 16´16 pixelated micro-LEDs for headlights by enhancing the reflectivity and coverage of the p-electrode," Phys. Status Solidi A 215 (10), 1700571-1–5 (2018). [Featured cover article in issue 10 of volume 215 (May, 2018)]

 

·         "Impact of electron flux on plasma damage-free sputtering of ultrathin indium-tin-oxide contact layer on p-GaN for InGaN/GaN light-emitting diodes," Adv. Sci. 5 (2), 1700637-1–10 (2018). (IF = 15.804)

 

·         "New insight into Ni-rich layered structure for next-generation Li rechargeable batteries," Adv. Energy Mater. 8 (4), 1701788-1–12 (2018). [Featured cover article in issue 4 of volume 8 (February, 2018)] (IF = 24.884)

 

·         "Temperature-dependent thermal conductivity of flexible yttria-stabilized zirconia substrate via 3ω technique," Phys. Status Solidi A 214 (10), 1700069-1–5 (2017). [Featured back cover article in issue 10 of volume 214 (October, 2017)]

 

·         "High-performance flexible thin-film transistors based on single-crystal-like germanium on glass," Adv. Electron. Mater. 2 (8), 1600041-1–7 (2016). [Featured frontispiece article in issue 8 of volume 2 (August, 2016)]

 

·         "Bendable III-N visible light-emitting diodes beyond mechanical flexibility:  Theoretical study on quantum efficiency improvement and color tunability by external strain," ACS Photon. 3 (3), 486–493 (2016). [Featured cover article in issue 3 of volume 3 (March, 2016)]

 

·         "Temperature-dependent resonance energy transfer from semiconductor quantum wells to graphene," Nano Lett. 15 (2), 896–902 (2015). (IF = 12.279)

·         "Ordered nanowire array blue/near-UV light emitting diodes," Adv. Mater. 22 (42), 4749–4753 (2010). (IF = 25.809)

 

·         (Invited paper) "Control of quantum confined Stark effect in InGaN-based quantum wells," IEEE J. Select. Topic. Quantum Electron. 15 (4), 1080–1091 (2009).

 

·         "Growth of uniformly aligned ZnO nanowire heterojunction arrays on GaN, AlN, and Al0.5Ga0.5N substrates," J. Am. Chem. Soc. 127 (21), 7920–7923 (2005). (IF = 14.695)

 

 

Books


1.   (Invited book) Jae-Hyun Ryou and Shahab Shervin, Flexible Devices Based on III-V Semiconductors - Applications in Electronics, Photonics and Energy, Springer International Publishing AG, Cham, Switzerland (in preparation).

 

2.  (Editor, Conference Proceeding) Christian Wetzel, Jae-Hyun Ryou, and Michael Manfra Ed., Special issue of Physica Status Solidi C:  Current Topics in Solid-State Physics, The Proceedings of the ISGN-5 (5th International Symposium on Growth of III-Nitrides), 12 (4-5), (2015).

 


Book Chapters

 

1. (Invited book chapter) Theeradetch Detchprohm, Jae-Hyun Ryou, Xiaohang Li, and Russell D. Dupuis, "Chapter 14. Future aspects of MOCVD technology," Metalorganic Vapor Phase Epitaxy (MOVPE): Growth, Materials Properties and Applications, S.J.C. Irvine and P. Capper Ed., Wiley, Hoboken, New Jersey, U.S.A. (2019) (ISBN-12:  978-11193130).

 

2. (Invited book chapter) Jae-Hyun Ryou and Wonseok Lee, "Chapter 3. GaN on sapphire substrates for visible light-emitting diodes," Nitride Semiconductor Light-Emitting Diodes (LEDs): Materials, Technologies, and Applications, 2nd Ed., J. J Huang, H.-C. Kuo, and S.-C. Shen Ed., Elsevier, Amsterdam, Netherlands (2017) (ISBN-13: 978-0081019429).

 

3. (Invited book chapter) Jae-Hyun Ryou, "Chapter 3. Gallium nitride (GaN) on sapphire substrates for visible LEDs," Nitride Semiconductor LEDs: Materials, Performance and Applications, J. J Huang, H.-C. Kuo, and S.-C. Shen Ed., Woodhead Publishing, Cambridge, U.K. (2013) (ISBN-13:  978-0857095077).

 


Patents Granted

 

1. Jae-Hyun Ryou, Shahab Shervin, and Seung-Hwan Kim, "Externally-strain-engineered semiconductor photonic and electronic devices and methods of making thereof and assemblies thereof," US Patent 10476234 (Nov. 12, 2019).

 

2. Jae-Hyun Ryou, "Flexible single-crystalline semiconductor device fabrication and methods of thereof," US Patent 10411035 (Sep. 10, 2019).

 

3. Jae-Hyun Ryou, "Flexible single-crystalline semiconductor device fabrication and methods of thereof," US Patent 9831273 (Nov. 27, 2017).

 


Patent Applications Filed

 

1. Jae-Hyun Ryou and Shahab Shervin, "Flexible single-crystal semiconductor heterostructures by direct growth and methods of making thereof," (international PCT filed to US PTO in Sep. 2017; Application #: PCT/US2017/050844).

 


Peer-Reviewed Journal Papers


Published

 

2021

 

1. S. Shervin, M. Moradnia, K. Alam, T. Tang, M.-H. Ji, J. Chen, S. Pouladi, T. Detchprohm, R. Forrest, J. Bao, R. D. Dupuis, and J.-H. Ryou, "Flexible single-crystalline GaN substrate by direct deposition of III-N thin films on polycrystalline metal tape," J. Mater. Chem. C 9 (7), 2243−2251 (2021). [Featured front-cover article in issue 7 of volume 9 (February, 2021)]

 

2. W. Gu, Y. Lu, R. Lin, W. Guo, Z.-H. Zhang, J.-H. Ryou, J. Yan, J. Wang, J. Li, and X. Li, "BAlN for III-nitride UV light emitting diodes: Undoped electron blocking layer," J. Phys. D: Appl. Phys. 54 (17), 175104-1−9 (2021).

 

3. N.-I. Kim, J. Chen, W. Wang, M. Moradnia, S. Pouladi, J. Y. Kim, M.-K. Kwon, and J.-H. Ryou, "Highly-sensitive skin-attachable self-powered eye-movement sensor using flexible non-hazardous piezoelectric thin film," Adv. Funct. Mater. 31 (8), 2008242-1−11 (2021).

 

2020

 

1.  D. Khatiwada, C. A. Favela, S. Sun, C. Zhang, S. Sharma, M. Rathi, P. Dutta, E. Galstyan, A. Belianinov, A. V. Ievlev, S. Pouladi, A. Fedorenko, J.-H. Ryou, S. Hubbard, and V. Selvamanickam, "High-efficiency single-junction p-i-n GaAs solar cell on roll-to-roll epi-ready flexible metal foils for low-cost photovoltaics," Prog. Photovoltaics: Res. Appl. 28 (11), 1107−1119 (2020).

 

2.  Y. Song, J. S. Lundh, W. Wang, J. Leach, D. Eichfeld, A. Krishnan, C. Perez, D. Ji, T. Borman, K. Ferri, J.-P. Maria, S. Chowdhury, J.-H. Ryou, B. Foley, and S. Choi, "The doping dependence of the thermal conductivity of bulk gallium nitride substrates," J. Electron. Packaging 142 (4), 041112-1−10 (2020).

 

3.  J.-Y. Kim, Y.-H. Cho, H.-S. Park, T.-H. Chung, S. Bang, A. Lee, M. S. Jeong, J.-H. Ryou, and M.-K. Kwon, "Localized surface plasmon-enhanced transparent conducting electrode for high-efficiency light emitting diode," Mater. Lett. 271, 127790-1–4 (2020).

 

4.  N.-I. Kim, Y.-L. Chang, J. Chen, T. Barbee, W. Wang, J. Y. Kim, M.-K. Kwon, S. Shervin, M. Moradnia, S. Pouladi, D. Khatiwada, V. Selvamanickam, and J.-H. Ryou, "Piezoelectric pressure sensor based on flexible gallium nitride thin film for harsh-environment and high-temperature applications," Sensor. Actuat. A - Phys. 305, 111940-1–9 (2020).

 

5.  W. H. Kim, Y. J. Jang, M. Kang, J.-Y. Kim, M. Han, K. Yang, J.-H. Ryou, and M.-K. Kwon, "High-performance color-converted full-color micro-LED arrays," Appl. Sci. 10, 2112-1–7 (2020).

 

6.  W. Wang, J. Chen, J. S. Lundh, S. Shervin, S. K. Oh, S. Pouladi, Z. Rao, J. Y. Kim, M.-K. Kwon, X. Li, S. Choi, and J.-H. Ryou, "Modulation of the 2-dimensional electron gas channel in flexible AlGaN/GaN high-electron-mobility transistors by mechanical bending," Appl. Phys. Lett. 116 (12), 123501-1–5 (2020). [Featured editor’s pick article in issue 12 of volume 116 (March, 2020)]

 

2019

 

1.  J.-Y. Kim, Y.-H. Cho, H.-S. Park, J.-H. Ryou, and M.-K. Kwon, "Mass transfer of microscale light-emitting diodes to unusual substrates by spontaneously formed vertical tethers during chemical lift-off," Appl. Sci. 9, 4243-1–8 (2019).

 

2.  J. Chen, H. Liu, W. Wang, N. Nabulsi, W. Zhao, J. Y. Kim, M.-K. Kwon, and J.-H. Ryou, "High durable, biocompatible and flexible piezoelectric pulse sensor using III-N thin film," Adv. Funct. Mater. 29 (37), 1903162-1–10 (2019). [Featured back-cover article in issue 37 of volume 29 (September, 2019)]

 

3.  J. Chen, N. Nabulsi, W. Wang, J. Y. Kim, M.-K. Kwon, and J.-H. Ryou, "Output characteristics of thin-film flexible piezoelectric generators: A numerical and experimental investigations," Appl. Energy 255, 113856-1–12 (2019).

 

4.  W. Wang, S. M. Lee, S. Pouladi, J. Chen, S. Shervin, S. Yoon, J. H. Yum, E. S. Larsen, C. W. Bielawski, B. Chatterjee, S. Choi, J. Oh, and J.-H. Ryou, "Polarization modulation effect of BeO on AlGaN/GaN high-electron-mobility transistors," Appl. Phys. Lett. 115 (10), 103502-1–5 (2019). [Featured editor’s pick article in issue 10 of volume 115 (September, 2019)]

 

5.  Y. Li, S. Sun, Y. Gao, Y. Yao, E. Galstyan, P. Rudra, M. Rathi, P. Dutta, S. Pouladi, J.-H. Ryou, and V. Selvamanickam, "Significant texture improvement in single-crystalline-like materials on low-cost, flexible metal tapes through growth of a silver thin film," J. Appl. Cryst. 52 (4), 898‒902 (2019).

 

6.  D. Khatiwada, M. Rathi, P. Dutta, S. Sicong, C. Favela, Y. Yao, Y. Li, S. Pouladi, J.-H. Ryou, and V. Selvamanickam, "Passivation studies on single junction GaAs thin film solar cells on flexible metal tapes for low cost photovoltaics," ACS Appl. Energy Mater. 2 (5), 3114‒3119 (2019).

 

7.  S. Pouladi, M. Asadirad, S. K. Oh, S. Shervin, J. Chen, W. Wang, C.-N. Manh, R. Choi, J. Kim, D. Khatiwada, M. Rathi, P. Dutta, V. Selvamanickam, and J.-H. Ryou, "Effects of grain boundaries on conversion efficiencies of single-crystal-like GaAs thin-film solar cells directly deposited on flexible metal tapes," Sol. Energy Mater. Sol. Cells 199, 122‒128 (2019).

 

8.  S. M. Lee, J. H. Yum, E. S. Larsen, S. Shervin, W. Wang, J.-H. Ryou, C. W. Bielawski, W. C. Lee, S. K. Kim, and J.-W. Oh, "Domain epitaxy of crystalline BeO films on GaN and ZnO substrates," J. Am. Ceram. Soc. 102 (6), 3745‒3752 (2019).

 

9.  Z. Ren, Y. Lu, H.-H. Yao, H. Sun, C.-H. Liao, J. Dai, C. Chen, J.H. Ryou, J. X. Yan, J. Wang, J. Li, and X. Li, "III-nitride deep UV LED without electron blocking layer," IEEE Photon. J. 11 (2), 8200511-1‒1 (2019).

 

10. (Invited review paper) S. K Oh, J. S. Lundh, S. Shervin, B. Chatterjee, D. K. Lee, S. Choi, J. S. Kwak, and J.-H. Ryou, "Thermal management and characterization of high-power wide-bandgap semiconductor electronic and photonic devices in automotive applications," J. Electron. Packaging 141, 020801-1‒17 (2019).

 

11. Y. Li, Y. Gao, Y. Yao, S. Sun, D. Khatiwada, S. Pouladi, E. Galstyan, M. Rathi, P. Dutta, A. Lytvynchuk, J.-H. Ryou, and V. Selvamanickam, "Direct synthesis of biaxially textured nickel disilicide thin films by magnetron sputter deposition on low-cost metal tapes for flexible silicon devices," Appl. Phys. Lett. 114 (8), 083502-1‒4 (2019).

 

12. P. Dutta, M. Rathi, D. Khatiwada, S. Sun, Y. Yao, B. Yu, S. Reed, M. Kacharia, J. Martinez, A. Litvinchuk, X. Pasala, S. Pouladi, B. Eslami, J.-H. Ryou, H. Ghasemi, P. Ahrenkiel, S. M. Hubbard, and V. Selvamanickam, "Flexible GaAs solar cells on roll-to-roll processed epitaxial Ge films on metal foils: a route towards low-cost and high-performance III-V photovoltaics," Energy Environ. Sci. 12, 756‒766 (2019).

 

13. J. Chen, S. K. Oh, N. Nabulsi, H. Johnson, W. Wang, and J.-H. Ryou, "Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using flexible III-nitride thin-film-based piezoelectric generator," Nano Energy 57, 670‒679 (2019).

 

14. S. Pouladi, M. Rathi, D. Khatiwada, M. Asadirad, S. K. Oh, P. Dutta, Y. Yao, Y. Gao, S. Sun, Y. Li, S. Shervin, K. H. Lee, V. Selvamanickam, and J.-H. Ryou, "High-efficiency flexible III-V thin-film photovoltaic solar cells based on single-crystal-like thin-film directly grown on metallic tapes," Prog. Photovoltaics: Res. Appl. 27 (1), 30‒36 (2019). [Featured cover article in issue 1 of volume 27 (January, 2019)]

 

15. S. M. Lee, Y. S. Jang, J. Jung, J. H. Yum, E. S. Larsen, C. W. Bielawski, W. Wang, J.-H. Ryou, H.-S. Kim, H.-T. Cha, and J.-W. Oh, "Atomic layer deposition of crystalline BeO on SiC," Appl. Surf. Sci. 469, 634‒640 (2019).

 

2018

1. Y. Li, H. Guo, Y. Yao, P. Dutta, M. Rathi, N. Zheng, A. Khadimallah, Y. Gao, S. Sun, J.-H. Ryou, P. Ahrenkiel, and V. Selvamanickam, "Defect reduction by liquid phase epitaxy of germanium on single-crystalline-like germanium templates on flexible, low-cost metal substrates," Cryst. Eng. Comm. 20 (41), 6573‒6579 (2018).

2. H. Sun, D. Priante, J.-W. Min, C. Zhao, M. K. Shakfa, R. C. Subedi, Z. Ren, K.-H. Li, R. Lin, T. K. Ng, J.-H. Ryou, X. Zhang, B. S. Ooi, X. Li, "Graded-index separated confinement heterostructure AlGaN nanowires: Towards ultraviolet laser diodes implantation," ACS Photon. 5 (8), 3305-3314 (2018).

3. S. Singh, S. Shervin, H. Sun, M. Yarali, J. Chen, R. Lin, K.-H. Li, X. Li, J.-H. Ryou, and A. Mavrokefalos, "Using mosaicity to tune thermal transport in polycrystalline AlN thin films," ACS Appl. Mater. Interfaces 10 (23), 20085-20094 (2018).

4. T. K. Kim, M. U. Cho, S. K. Oh, K. J. Son, B. Chatterjee, J.-H. Ryou, S. Choi, and J. S. Kwak, "Improved light output power of 16x16 pixelated micro-LEDs for headlights by enhancing the reflectivity and coverage of the p-electrode," Phys. Status Solidi A 215 (10), 1700571-1-5 (2018). [Featured cover article in issue 10 of volume 215 (May, 2018)]

5. J. Chen, S. K. Oh, H. Zou, S. Shervin, W. Wang, S. Pouladi, Y. Zi, Z. L. Wang, and J.-H. Ryou, "High-output lead-free flexible piezoelectric generators based on GaN thin film," ACS Appl. Mater. Interfaces 10 (15), 12839-12846 (2018).

6. K. J. Son, T. K. Kim, Y.-J. Cha, S. K. Oh, S.-J. You, J.-H. Ryou, and J. S. Kwak, "Impact of electron flux on plasma damage-free sputtering of ultrathin indium-tin-oxide contact layer on p-GaN for InGaN/GaN light-emitting diodes," Adv. Sci. 5 (2), 1700637-1-10 (2018).

7. S. Shervin, S. K. Oh, H. J. Park, K.-H. Lee, M. Asadirad, S. H. Kim, J. Kim, S. Pouladi, S.-N. Lee, X. Li, J. S. Kwak, and J.-H. Ryou, "Flexible deep-ultraviolet light-emitting didoes for significant improvement of quantum efficiencies by external bending," J. Phys. D: Appl. Phys. 51 (10), 105105-1-7 (2018).

8. W. Lee, S. Muhammad, T. Kim, H. Kim, E. Lee, M. Jeong, S. Son, J.-H. Ryou, and W. S. Yoon, "New insight into Ni-rich layered structure for next-generation Li rechargeable batteries," Adv. Energy Mater. 8 (4), 1701788-1-12 (2018). [Featured cover article in issue 4 of volume 8 (February, 2018)]

9. S. Jeong, S. K. Oh, J.-H. Ryou, K.-S. Ahn, K. M. Song, and H. Kim, "Monolithic inorganic semiconductor heterojunction white light-emitting diodes," ACS Appl. Mater. Interfaces 10 (4), 3761-3768 (2018).

2017

 

1. S. M. Lee, J. H. Yum, S. Yoon, E. S. Larsen, W. C. Lee, S. K. Kim, S. Shervin, W. Wang, J.-H. Ryou, C. W. Bielawski, and J. Oh, "Atomic layer deposition of single-crystalline BeO epitaxially grown on GaN substrates,"ACS Appl. Mater. Interfaces 9 (48), 41973-41979 (2017).

 

2. S. Sing, M. Yarali, S. Shervin, V. Venkateswaran, K. Olenick, J. A. Olenick, J.-H. Ryou, and A. Mavrokefalos, "Temperature-dependent thermal conductivity of flexible yttria-stabilized zirconia substrate via 3ω technique,"Phys. Status Solidi A 214 (10), 1700069-1-5 (2017). [Featured back cover article in issue 10 of volume 214 (October, 2017)]

 

3. S. K. Oh, M. U. Cho, J. Dallas, T. Jang, D. G. Lee, S. Pouladi, J. Chen, W. Wang, S. Shervin, H. Kim, S. Shin, S. Choi, J. S. Kwak, and J.-H. Ryou, "High-power flexible AlGaN/GaN heterostructure field-effect transistors with negative differential conductivity suppression," Appl. Phys. Lett. 111 (13), 133501-1-5 (2017).

 

4. M. Rathi, P. Dutta, N. Zheng, Y. Yao; D. Khatiwada, Y. Gao, S. Sun, Y. Li, S. Pouladi, P. Ahrenkiel, J.-H. Ryou, and V. Selvamanickam, "High opto-electronic quality n-type single-crystalline-like GaAs thin films on flexible metal substrates," J. Mater. Chem. C 5 (31), 7919-7926 (2017).

 

5. M. Baek, M. Oh, B. Parida, M. S. Kim, J.-H. Ryou, and H. Kim, "Hybrid oblique-angle deposited ITO/silver nanowire transparent conductive electrodes for brighter light emitters," IEEE Trans. Electron Device. 64 (9), 3690-3695 (2017).

 

6.  E. Jung, S. Jeong, J.-H. Ryou, and H. Kim, "Deep-trap states of GaN-based light emitting diodes analyzed by space charge limited conduction model," J. Nanosci. Nanotechnol. 17 (10), 7339-7343 (2017).

 

7. M. Oh, H. J. Jeong, M. S. Jeong, K.-S. Ahn, K.-K. Kim, J.-H. Ryou, and H. Kim, "Functional hybrid indium-tin-oxide transparent conductive electrodes for light-emitters," J. Alloy. Compound. 724, 813-819 (2017).

 

8. W. Wang, S. Shervin, S. K. Oh, J. Chen, Y. Huai, S. Pouladi, H. Kim, S.-N. Lee, and J.-H. Ryou, "Flexible AlGaInN/GaN heterostructures for high-hole-mobility transistors," IEEE Electron Device Lett. 38 (8), 1086-1089 (2017).

 

9. B. Parida, S. Kim, M. Oh, S. Jeong, M. K. Baek, J.-H. Ryou, and H. Kim, "Nanostructured NiO/Si heterojunction photodetector," Mater. Sci. Semicon. Process. 71, 29-34 (2017).

 

10. S. Kim, K.-S. Ahn, J.-H. Ryou, and H. Kim, "Temperature-dependent DC characteristics of AlInN/GaN high-electron-mobility transistors," Electron. Mater. Lett. 13 (4), 302-306 (2017).

 

11. M. Asadirad, S. Pouladi, S. Shervin, S. K. Oh, K. H. Lee, J. Kim, S.-N. Lee, Y. Gao, P. Dutta, V. Selvamanickam, and J.-H. Ryou, "Numerical simulation for operation of flexible thin-film transistors with bending," IEEE Electron Device Lett. 38 (2), 217-220 (2017).

 

12. H. Brahmi, S. Ravipati, S. Shervin, W. Wang, J.-H. Ryou, and A. Mavrokefalos, "Electrical and optical properties of sub-10nm nickel silicide films for silicon solar cells," J. Phys. D: Appl. Phys. 50 (3), 035102-1-10 (2017).

 

13. J.-H. Lee, S.-H. Han, K.-R. Song, J.-H. Ryou, H. Na, and S.-L. Lee, "Effect of SiO2 hexagonal pattern on the crystal and optical properties of epitaxial lateral overgrown semipolar (11-22) GaN film," Microelectron. Eng. 168, 32-36 (2017).

 

14. S. K. Oh, T. Jang, S. Pouladi, Y. J. Jo, H.-Y. Ko, J.-H. Ryou, and J. S. Kwak, "Output power enhancement in AlGaN/GaN heterostructure filed-effect transistors with multi-level metallization," Appl. Phys. Express 10 (1), 016502-1-3 (2017).

 

2016

1. Y. Gao, M. Asadirad, Y. Yao, P. Dutta, E. Galstyan, S. Shervin, K. H. Lee, S. Pouladi, S. Sun, Y. Li, M. Rathi, J.-H. Ryou, and V. Selvamanickam, "High-performance flexible thin-film transistors based on single-crystal-like silicon epitaxially grown on metal tape by roll-to-roll continuous deposition process," ACS Appl. Mater. Interfaces 8 (43), 29565-29572 (2016).

2. S. H. Kim, K. H. Lee, H. J. Park, S. Shervin, M. Asadirad, S.-N. Lee, J. S. Kwak, and J.-H. Ryou, "Patterned Ga2O3 for current blocking and optical scattering in visible light-emitting diodes," Phys. Status Solidi A 213 (10), 2769-2772 (2016)

3. K.-H. Lee, M. Asadirad, S. Shervin, S. K Oh, J. T. Oh, J.-O. Song, Y.-T. Moon, and J.-H. Ryou, "Thin-film-flip-chip LEDs grown on Si substrate using wafer-level chip-scale package," IEEE Photon. Technol. Lett. 28 (18), 1956-1959 (2016).

4. M. Asadirad, Y. Gao, P. Dutta, Y. Yao, S. Shervin, S. Sun, S. Ravipati, S.-H. Kim, K. H. Lee, V. Selvamanickam, and J.-H. Ryou, "High-performance flexible thin-film transistors based on single-crystal-like germanium on glass," Adv. Electron. Mater. 2 (8), 1600041-1-7 (2016). [Featured frontispiece article in issue 8 of volume 2 (August, 2016)]

5. J. Kim, M.-H. Ji, T. Detchprohm, R. D. Dupuis, S. Shervin, and J.-H. Ryou, "Effect of lattice-matched InAlGaN electron-blocking layer on hole transport and distribution in InGaN/GaN multiple quantum wells of visible light-emitting diodes," Phys. Status Solidi A 213 (5), 1296-1301 (2016).

6. S. H. Kim, S. Singh, S. K. Oh, D. K. Lee, K. H. Lee, S. Shervin, M. Asadirad, V. Venkateswaran, K. Olenick, J. Olenick, S.-N. Lee, J. S. Kwak, A. Mavrokefalos, and J.-H. Ryou, "Visible light-emitting diodes on flexible ceramic substrate with improved thermal management," IEEE Electron Device Lett. 37 (5), 615-617 (2016).

7. H. J. Park, H. J. Bae, J. B. Park, J. S. Ha, T. Jeong, J. H. Baek, S. H. Kim, and J.-H. Ryou, "Enhanced wall-plug efficiency in monolithically-integrated vertical light-emitting-diode cells based on III-nitride heterostructures," J. Vac. Sci. Tech. B 34 (2), 021206-1-5 (2016).

8. S. Shervin, S.-H. Kim, M. Asadirad, S. Yu. Kapov, D. Zimina, and J.-H. Ryou, "Bendable III-N visible light-emitting diodes beyond mechanical flexibility:  Theoretical study on quantum efficiency improvement and color tunability by external strain," ACS Photon. 3 (3), 486-493 (2016). [Featured cover article in issue 3 of volume 3 (March, 2016)]

9. S. Kim, J.-H. Ryou, R. D. Dupuis, and H. Kim, "Reduced gate leakage current of AlInN:Mg/GaN high electron mobility transistors," Electron. Lett. 52 (2), 157-159 (2016).

2015

1. X.-H. Li, H. Xie, F. A. Ponce, J.-H. Ryou, T. Detchprohm, and R. D. Dupuis, "Onset of surface stimulated emission at 260 nm at room temperature from AlGaN multiple-quantum wells grown on sapphire substrate," Appl. Phys. Lett. 107 (24), 241109-1-4 (2015).

2. S. Shervin, S.-H. Kim, M. Asadirad, S. Ravipati, K.-H. Lee, K. Bulashevich, and J.-H. Ryou, "Strain-effect transistors:  Theoretical study on the effects of external strain on III-nitride high-electron-mobility transistors on flexible substrates," Appl. Phys. Lett. 107 (19), 193504-1-5 (2015).

3. J. Kim, M.-H. Ji, T. Detchprohm, R. D. Dupuis, J.-H. Ryou, A. K. Sood, N. K. Dhar, and J. Lewis, "Comparison of AlGaN p-i-n ultraviolet avalanche photodiodes grown on free-standing GaN and sapphire substrates," Appl. Phys. Express 8 (12), 122202-1-4 (2015).

4. J. Kim, M.-H. Ji, T. Detchprohm, R. D. Dupuis, A. M. Fischer, F. A. Ponce, and J.-H. Ryou, "Effect of Group-III precursors on unintentional gallium incorporation during epitaxial growth of InAlN layers by metalorganic chemical vapor deposition," J. Appl. Phys. 118 (12), 125303-1-6 (2015).

5. K. H. Lee, H. J. Park, S. H. Kim, M. Asadirad, Y.-T. Moon, J. S. Kwak, and J.-H. Ryou, "Light extraction efficiency control in AlGaN-based deep-ultraviolet flip-chip light-emitting diodes:  A comparison to visible flip-chip light-emitting diodes," Opt. Express 23 (16), 20340-20349 (2015).

6. Y.-S. Liu, T.-T. Kao, Md. M. Satter, Z. Lochner, S.-C. Shen, T. Detchprohm, P. D. Yoder, R. D. Dupuis, J.-H. Ryou, A. M. Fischer, Y. O. Wei, H. Xie, and F. A. Ponce, "Inverse-tapered p-waveguide for efficient vertical hole transport in high-[Al] AlGaN multiple-quantum well double-heterojunction emitters grown by metalorganic chemical vapor deposition on AlN substrates," IEEE Photon. Technol. Lett. 27(16), 1768-1771 (2015).

7. K. H. Lee, S.-H. Kim, W.-S. Lim, J.-O. Song, and J.-H. Ryou, "Visible light-emitting diodes with thin-film-flip-chip-based wafer-level chip-scale package technology with anisotropic conductive film bonding," IEEE Electron Device Lett. 36 (7), 702-704 (2015).

8. J. Kim, M.-H. Ji, T. Detchprohm, J.-H. Ryou, R. D. Dupuis. A. K. Sood, and N. K. Dhar, "AlxGa1-xN ultraviolet avalanche photodiodes with avalanche gain greater than 105 grown on GaN substrate," IEEE Photon. Technol. Lett. 27 (6), 642-645 (2015).

9. Y.-J. Yu, K. S. Kim, J. Nam, S. R. Kwon, H. Byun, K. Lee, J.-H. Ryou, R. D. Dupuis, J. Kim, G. Ahn, S. Ryu, M.-Y. Ryu, and J. S. Kim, "Temperature-dependent resonance energy transfer from semiconductor quantum wells to graphene," Nano Lett. 15 (2), 896-902 (2015).

10. H. M. Oh, C.-R. Lee, J. S. Kim, K. Pyun, K. J. Lee, M. S. Jeong, Y. H. Kim, J.-Y. Leem, and J.-H. Ryou, "Periodic variation in the electroluminescence intensity on a single pattern from InGaN/GaN light-emitting diodes fabricated on lens-shaped patterns," J. Kor. Phys. Soc. 66 (2), 266-269 (2015).

2014


1. B. Jo, C.-R. Lee, J. S. Kim, W. S. Han, J. H. Song, J.-H. Ryou, J. H. Lee, and J.-Y. Leem, "High-power continuous-wave operation of InP-based InAs quantum-dot laser with dot-in-a-well structure and strain-modulating layer," Laser Phys. Lett. 11 (11), 115815-1-6 (2014).

2. B. Jo, C.-R. Lee, J. S. Kim, W. S. Han, J. H. Song, J.-Y. Leem, S. K. Noh, J.-H. Ryou, and R. D. Dupuis, "Investigation on the lasing characteristics of InAs/InGaAsP quantum dots with additional confinement structures," J. Crystal Growth 393, 59-63 (2014).

3. J. Kim, M. H. Ji, D. Yuan, R. Guo, J.-P. Liu, M. Asadirad, T. Detchprohm, M.-K. Kwon, R. D. Dupuis, S. Das, and J.-H. Ryou, "Direct periodic patterning of GaN-based light-emitting diodes by three-beam interference laser ablation," Appl. Phys. Lett. 104 (14), 1411105-1-4 (2014).

4. J. Kim, Z. Lochner, M.-H. Ji, S. Choi, H. J. Kim, J. S. Kim, R. D. Dupuis, A. M. Fischer, R. Juday, Y. Huang, T. Li, J. Y. Huang, F. A. Ponce, and J.-H. Ryou, "Origins of unintentional incorporation of gallium in InAlN layers during epitaxial growth, part II: Effects of underlying layers and growth chamber conditions," J. Crystal Growth 388, 143-149 (2014).

5. S. Choi, H. J. Kim, Z. Lochner, J. Kim, R. D. Dupuis, A. M. Fischer, R. Juday, Y. Huang, T. Li, J. Y. Huang, F. A. Ponce, and J.-H. Ryou, "Origins of unintentional incorporation of gallium in AlInN layers during epitaxial growth, part I: Growth of AlInN on AlN and effects of prior coating," J. Crystal Growth 388, 137-42 (2014).

2013

1. S. Kim, H. J. Kim, S. Choi, Z. Lochner, J.-H. Ryou, R. D. Dupuis, K.-S. Ahn, and H. Kim, "Electrical characteristics of Ti/Al contacts on AlInN:Mg/GaN heterostructures," 52 (10), 10MA07-1-4 (2013).

2. S. Kim, H. J. Kim, S. Choi, Z. Lochner, J.-H. Ryou, R. D. Dupuis, K.-S. Ahn, and H. Kim, "Electrical characteristics of Pt Schottky contacts on AlInN:Mg/GaN heterostructures," 52 (10), 10MA05-1-4 (2013).

3. Z. Lochner, X.-H. Li, T.-T. Kao, Md. M.Satter, H. J. Kim, S.-C. Shen, P. D. Yoder, J.-H. Ryou, R. D. Dupuis, K. W. Sun, Y. Wei, T. Li, A. M. Fischer, and F. A. Ponce, "Stimulated emission at 257 nm from optically-pumped AlGaN/AlN heterostructure on AlN substrate," 210 (9), 1968-1970 (2013).

4. J. Kim, M.-H. Ji, Z. Lochner, S. Choi, J. P. Liu, Md. M. Satter, P. D. Yoder, R. D. Dupuis, R. Juday, A. M. Fischer, F. A. Ponce, and J.-H. Ryou, "Improved hole transport by p-InGaN layer in multiple quantum wells of visible LEDs," IEEE Photon. Technol. Lett.25 (18), 1789-1792 (2013).

5. R. Juday, A. M. Fischer, Y. Huang, J. Y. Huang, H. J. Kim, J.-H. Ryou, R. D. Dupuis, D. P. Bour, and F. A. Ponce, "Hydrogen-related, deeply-bound excitons in Mg-doped GaN films," Appl. Phys. Lett. 103 (8), 082103-1-5 (2013).

6. Z. Lochner, T.-T. Kao, Y.-S. Liu, X.-H. Li, Md. M.Satter, S.-C. Shen, P. D. Yoder, J.-H. Ryou, R. D. Dupuis, Y. Wei, H. Xie, A. Fischer, and F. A. Ponce, "Deep-ultraviolet lasing at 243 nm from photo-pumped AlGaN/AlN heterostructure on AlN substrate," Appl. Phys. Lett. 102 (10), 101110-1-4 (2013).

7. S. Kim, J.-H. Ryou, R. D. Dupuis, and H. Kim, "Carrier transport mechanism of low resistance Ti/Al/Au ohmic contacts to AlInN/GaN heterostructures," Appl. Phys. Lett. 102 (5), 052107-1-4 (2013).

2012

1. D. W. Park, C.-R. Lee, J. S. Kim, S. J. Lee, Y. H. Kim, S. K. Noh, H. M. Oh, Y. H. Kim, J.-Y. Leem, M. S. Jeong, and J.-H. Ryou, "Self-catalyzed GaAs nanowires without Ga droplets formed on Si (111)," J. Kor. Phys. Soc. 61 (12), 2017-2021 (2012).

2. S. Choi, M.-H. Ji, J. Kim, H. J. Kim, Md. M.Satter, J.-H. Ryou, P. D. Yoder, R. D. Dupuis, A. M. Fischer, and F. A. Ponce, "Efficiency droop due to electron spill-over and limited hole transport in III-nitride visible light-emitting diodes employing lattice-matched InAlN electron blocking layers," Appl. Phys. Lett. 101 (16), 161110-1-5 (2012).