Semiconductor Nanostructure Research Group
Exploring new structures, materials and physics behind.
In Semiconductor Nanostructure Research Group at JBNU, We focus on the high quality material growth and deposition using growth/deposition equipement such as molecular beam epitaxy (MBE) and sputtering deposition. We explorer new materials, develop new structures of conventional materials, and see the physics behind them for advanced functional devices.
전북대학교 반도체 나노구조 연구실은 스퍼터링과 MBE 등의 장치를 이용하여 고품질 반도체 소재의 증착 및 성장을 연구합니다. 또한 이들을 기술적 도구로 활용하여 새로운 소재 및 새로운 나노 구조를 탐구하는 동시에, 이들이 새로운 반도체 소자의 동작 가능성을 어떻게 보여주는지 연구합니다.
January 2024
An atomically clean surface is a must for epitaxial regrowth and device fabrication.
Oxide islands spontaneously form on II-VI semiconductor surfaces limiting regrowth, thus removal of the islands via thermal annealing is investigated for ZnSe/GaAs.
Annealing at 200°C shows good morphological and optical properties in both layers and surface is further smoothened at 300°C degrading optical properties of both layers.
The article is just accepted for the publication in Materials Science in Semiconductor Processing and is available online (https://doi.org/10.1016/j.mssp.2024.108176).
January 2024
A molecular beam epitaxy (MBE) system is just shipped.
The system is assigned to the growth of plasma-assisted semiconductor epitaxy.
December 2023
InP substrate is well-known for epitaxy growth of various semiconductor devices. However, InP substrate is small, fragile and expensive increasing the device cost.
To overcome the issues, we propose direct growth of InP on vicinal GaAs substrate. The growth was aided by AlAs/GaAs superlattice-induced quasi-quantum wires (QWRs).
With the presence of QWRs or lateral composition modulation (LCM) structure, InP quality is enhanced with reduced defect density.
The article is just accepted for the publication in Materials Science in Semiconductor Processing and is available online (https://doi.org/10.1016/j.mssp.2023.108060).
November 2023
A review paper on the growth of p-Si using AlC is accepted for publication in 전기전자재료학회지 Journal of the Korean Institute of Electrical and Electronic Material Engineers.
This paper is first-authored by 김도현 Dohyun Kim, an undergrad intern of Semiconductor Nanostructure Research Group.
The article is available online (https://doi.org/10.4313/JKEM.2024.37.1.3).
October 2023
HfS2 as a transition dichalcogenides has predicted superior physical properties.
Increased reflectance (DRS) in 500-900 nm is observed from the sample of high HfCl4 supply.
Other measurements also confirmed increased reflectance is evidence of HfS2 formation.
The article is just accepted for publication in Current Applied Physics and is available online (https://doi.org/10.1016/j.cap.2023.10.011).
This paper is first-authored by 황주찬 Juchan Hwang, a MS student of Semiconductor Nanostructure Research Group.
October 2023
Bound state in continuum (BIC) is completely confined state of open optical structure having infinite Q-factor, and must be turned into quasi-BICs having a finite Q-factor.
A novel asymmetric hetero-bilayer metasurface is proposed as a route of quasi-BIC, and the effect of perturbation and grating material of the structure are investigated.
A model gas sensor of the structure can distinguish a small refractive-index change.
The article is just accepted for publication in Optics and Laser Technology (https://doi.org/10.1016/j.optlastec.2023.110191).
September 2022
InGaN is an important alloy of having viable bandgap energy by changing In content.
Partially relaxed InGaN samples of different compositions were grown using PAMBE.
Vertical profiling of ultrafast carrier dynamics of InGaN were performed by OPTP.
Fast decay is caused by hot carrier cooling due to uniformly distributed oxygen.
Slow decay is due to carrier localization by V-defect at InGaN/GaN interface.
The article is available at https://doi.org/10.1016/j.apsusc.2022.155020.
September 2021
Liquid and gas sensors are designed based on critical coupling condition of Fabry-Perot cavity.
A high signal contrast at the target wavelength is achieved with carefully controlled design parameters of a Si grating.
The sensors present high signal contrast with the deviation of refractive index depending on analytes.
A collaborative work with Dr Gyeong Cheol Park of Electronics and Telecommunications Research Institute (ETRI).
The article is available at https://doi.org/10.1038/s41598-021-98654-w.
August 2021
Above-bandgap photo-irradiation improves low temperature epitaxy.
Photo-irradiation reduces planar defects but enhances interface intermixing .
We found that the high photon intensities damage bulk ZnSe but not the interface.
We also found that proper substrate temperature and irradiation selection aids heterovalent epitaxy.
A collaborative work with Dr Kirstin Alberi of National Renewable Energy Laboratory and Dr Jung-Wook Min of KAUST.
The article is available at https://doi.org/10.1016/j.apsusc.2021.151067.
March 2021
A tunable dual-wavelength absorption (TDWA) switch based on an asymmetric guided mode resonance (AGMR) structure is proposed.
For switching, the TDWA between an absorptive or reflective mode with each on-/off-state, the chemical potential of graphene is tuned.
The TDWA structure would be useful for graphene-based dual-wavelength NIR image sensors and dual-wavelength on-off optical mirrors.
A collaborative work with Dr Gyeong Cheol Park at Technical University of Denmark, DTU (Currently at ETRI).
The article is available at https://doi.org/10.1364/OE.416394.
