Publications

2025

[2] Complex Conductivity Characterization of InGaZnO Films Using Terahertz Time-Domain Spectroscopy 

Sein Lee†, Junho Ryeom†, Jang-Yeon Kwon, Geunchang Choi*, Seok Daniel Namgung*

Applied Surface Science, 714, 164388 (2025) PDF

[1] Layer-Dependent Characterization of Two-Dimensional Lead-Halide Perovskite Crystals 

Junho Ryeom, Dae Young Park, Young-Mi Bahk, Geunchang Choi*, and Mun Seok Jeong*

Journal of Alloys and Compounds, 1030, 180811 (2025) PDF

2023

[4] Efficient electroluminescence in doped-GaAs via terahertz metamaterials 

Taehee Kang, Jindong Song, Dai-Sik Kim* and Geunchang Choi* 

Applied Physics Express 16, 102004 (2023) PDF

[3] Terahertz conductivity of high-quality indium films deposited using a substrate cooling method 

Geunchang Choi†, Dong-Hwan Choi†, Junho Ryeom†, Dae Young Park, Wu-Sin Kim , Ju-Jin Kim, Young-Mi Bahk, and Mun Seok Jeong* 

Current Applied Physics 52, 80-84 (2023) PDF

[2] Terahertz nanofuse by a single nanowire-combined nanoantenna

Geunchang Choi†, Yeeun Roh†, and Minah Seo*

Nanophotonics 12(13): 2545-2551 (2023) PDF

[1] Enhanced terahertz nonlinear response of GaAs by the tight field confinement in a nanogap  

Dasom Kim, Dai-Sik Kim*, and Geunchang Choi* 

APL Photonics 8 (3), 036107 (2023) PDF (Selected as an Editor's Pick)

2022

[2] Monitoring Temporal Evolution of the Dehydration Process of the Caffeine Hydrate with Terahertz Spectroscopy 

Hajung Park†, Nahun Kim†, Jaeyung Yu, Jiyeah Rhie, Geunchang Choi*, and Young-Mi Bahk*

Journal of the Korean Physical Society 81, 1225-1230 (2022) PDF

[1] Evaluation of moisturizing cream using terahertz time-domain spectroscopy 

Geunchang Choi, Do-Hee Lee, Ikpyeong Park, Daecheol Kang, Hyun Kyung Lee, Jiyeah Rhie, and Young-Mi Bahk*

Current Applied Physics 39, 84 (2022) PDF

2021

[2] Detecting Defects in Electric Power Cables by Using Terahertz Time-domain Spectral Imaging Technology

Hajung PARK, Taewon GOO, Young-Mi BAHK*, Geunchang CHOI

New Phys.: Sae Mulli 71: 639-644 (2021) PDF

[1] Augmented All-optical Active Terahertz Device using Graphene-based Metasurface

Geunchang Choi*, Tuan Khanh Chau, Sung Ju Hong, Dasom Kim, Sung Hyuk Kim, Dai-Sik Kim, Dongseok Suh, Young-Mi Bahk*, Mun Seok Jeong*

Advanced Optical Materials 9 (16), 2100462 (2021) PDF

~ 2020

[15] Colloidal MoS2 van der Waals Template for Growing Highly Uniform Nanomaterials

Kang-Nyeoung Lee, Dae Young Park, Geunchang Choi, Duc Anh Nguyen, Young Chul Choi, Mun Seok Jeong*

ACS Applied Materials & Interfaces 12 (31), 35716-35724 (2020) PDF

[14] Graphene-assisted biosensing based on terahertz nanoslot antennas

Geunchang Choi*, Sung Ju Hong*, Young-Mi Bahk*

Scientific Reports 9 (1), 1-5 (2019) PDF

[13] Terahertz rectification in ring-shaped quantum barriers

Taehee Kang, RH Joon-Yeon Kim, Geunchang Choi, Jaiu Lee, Hyunwoo Park, Hyeongtag Jeon, Cheol-Hwan Park, Dai-Sik Kim*

Nature communications 9 (1), 1-8 (2018) PDF

[12] Enhanced Surface Carrier Response by Field Overlapping in Metal Nanopatterned Semiconductor

Geunchang Choi, Taehee Kang, Minah Seo, Dai-Sik Kim*, Young-Mi Bahk*

ACS Photonics 5 (12), 4739-4744 (2018) PDF (Inside back cover)

[11] Control of optical nanometer gap shapes made via standard lithography using atomic layer deposition

Jiyeah Rhie*, Dukhyung Lee, Young-Mi Bahk, Jeeyoon Jeong, Geunchang Choi, Youjin Lee, Sunghwan Kim, Seunghun Hong, Dai-Sik Kim

Journal of Micro/Nanolithography, MEMS, and MOEMS 17 (2), 023504 (2018) PDF

[10] Giant Field Enhancements in Ultrathin Nanoslots above 1 Terahertz

Dasom Kim, Jeeyoon Jeong, Geunchang Choi, Young-Mi Bahk, Taehee Kang, Dukhyung Lee, Bidhek Thusa, Dai-Sik Kim*

ACS Photonics 17 (2), 023504 (2018) PDF

[9] Enhanced Terahertz Shielding of MXenes with Nano‐Metamaterials

Geunchang Choi, Faisal Shahzad, Young‐Mi Bahk, Young Min Jhon, Hyunchul Park, Mohamed Alhabeb, Babak Anasori, Dai‐Sik Kim, Chong Min Koo, Yury Gogotsi*, Minah Seo*

Advanced Optical Materials 6 (5), 1701076 (2018) PDF 

(Selected to be included in the Best of Advanced Optical Materials 2018 virtual issue)

[8] Terahertz Nanoprobing of Semiconductor Surface Dynamics

Geunchang Choi, Young-Mi Bahk, Taehee Kang, Yoojin Lee, Byung Hee Son, Yeong Hwan Ahn, Minah Seo*, Dai-Sik Kim*

Nano Letters 17 (10), 6397-6401 (2017) PDF

[7] Terahertz transmission through rings of quantum dots-nanogap

Laxmi-Narayan Tripathi, Young-Mi Bahk, Geunchang Choi, Sanghoon Han, Namkyoo Park, Dai-Sik Kim*

Applied Physics Express 9 (3), 032001 (2016) PDF

[6] Quantum dots-nanogap metamaterials fabrication by self-assembly lithography and photoluminescence studies

Laxmi Narayan Tripathi, Taehee Kang, Young-Mi Bahk, Sanghoon Han, Geunchang Choi, Jiyeah Rhie, Jeeyoon Jeong, Dai-Sik Kim*

Optics Express 23 (11), 14937-14945 (2015) PDF

[5] Plasmon enhanced terahertz emission from single layer graphene

Young-Mi Bahk, Gopakumar Ramakrishnan, Jongho Choi, Hyelynn Song, Geunchang Choi, Yong Hyup Kim, Kwang Jun Ahn, Dai-Sik Kim*, Paul CM Planken*

ACS Nano 8 (9), 9089-9096 (2014) PDF

[4] Cancer cell imaging by stable wet near-field scanning optical microscope with resonance tracking method

Kyoung-Duck Park, Doo Jae Park, Mun Seok Jeong, Geun Chang Choi, Seung Gol Lee, Clare Chisu Byeon, Soo Bong Choi*

Journal of the Korean Physical Society 64 (10), 1500-1503 (2014) PDF

[3] A resonance tracking method for stable operation of a near-field scanning optical microscope in liquid environment 

Doo Jae Park, Kyoung-Duck Park, Geun Chang Choi, Seung Gol Lee, Clare Chisu Byeon, Mun Seok Jeong, Soo Bong Choi*

Current Applied Physics 14, S12-S16 (2014) PDF

[2] Operation of a wet near-field scanning optical microscope in stable zones by minimizing the resonance change of tuning forks

Kyoung-Duck Park, Doo Jae Park, Seung Gol Lee, Geunchang Choi, Dai-Sik Kim, Clare Chisu Byeon, Soo Bong Choi, Mun Seok Jeong*

Nanotechnology 25 (7), 075704 (2014) PDF

[1] Simple and reliable light launch from a conventional single-mode fiber into a helical-core fiber through an adiabatically tapered splice 

Hyuntai Kim, Jongki Kim, Yongmin Jung, Luis Alonso Vazquez-Zuniga, Seung Jong Lee, Geunchang Choi, Kyunghwan Oh, Pu Wang, WA Clarkson, Yoonchan Jeong*

Optics Express 20 (23), 25562-25571 (2012) PDF