고려대학교 · Materials Science
이 교수의 연구실은 nitride 계 반도체, 특히 GaN 및 InGaN 기반의 전자 및 광전자 소자에 초점을 맞추고 있습니다. Si 도핑에 의한 잔류 응력 완화, 광학적 특성 변화, 그리고 전하 수송 메커니즘의 이해를 핵심 연구 주제로 삼고 있으며, 특히 고도로 도핑된 GaN 에피레익스와 나노소재를 활용한 고성능 LED 및 센서 기술 개발에 기여하고 있습니다. 또한, 표면 증폭 라만 스펙트로스코피(SERS) 및 광촉매 나노복합체를 활용한 고감도 분석 기술 개발도 진행 중입니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
We report a systematic study accomplished with a series of undoped and Si-doped GaN epilayers grown on sapphire (0001) with the carrier concentration of 4.0×1017−1.6×1019 cm−3 in order to investigate the evolution of stress relaxation and yellow luminescence by Si incorporation. As the Si doping becomes higher, the bound exciton peaks are gradually shifted to lower energy due to relaxation of the thermal residual stress with the linear coefficient of ΔE/Δσ∥=42 meV/GPa. The present results show t
We investigate the optical properties of two sets of Si-doped GaN epitaxial layers with different degree of compensation. The electron concentration dependence of the band-gap energy measured by photoluminescence is interpreted as band-gap narrowing effect and evaluated by a simple relation. The photoluminescence peak positions of heavily compensated samples are shifted downward with respect to those of moderately compensated samples, and the down shift becomes larger at higher electron density.
We report the Si-doping-induced relaxation of residual stress in GaN epitaxial layers grown on (0001) sapphire substrate by the metalorganic vapor phase epitaxy technique. Micro-Raman spectroscopy is used to assess stress situation in the films with systematically modulated doping concentration from 4.0×1017 up to 1.6×1019 cm−3. As the Si-doping concentration increases, a monotonic decrease of the E2 phonon frequency is observed, which signifies gradual relaxation of the stress in the film. The
Noble metal-based surface-enhanced Raman spectroscopy (SERS) has enabled the simple and efficient detection of trace-amount molecules via significant electromagnetic enhancements at hot spots. However, the small Raman cross-section of various analytes forces the use of a Raman reporter for specific surface functionalization, which is time-consuming and limited to low-molecular-weight analytes. To tackle these issues, a hybrid SERS substrate utilizing Ag as plasmonic structures and GaN as charge
As a good stabilizer, [BMIM]BF4 ionic liquid (IL) has been successfully utilized to assist preparation of Ag nanoparticles (NPs) decorated on CeO2 supports. The obtained IL-stabilized Ag-CeO2 nanocomposite showed better photocatalytic degradation activity (92%) of Auramine O (AO) dye as compared with pure CeO2 (35%) NPs and IL-free Ag-CeO2 (65%) nanocomposite after 90 min of visible light irradiation. The improvement could be attributable to small size (5 nm) of IL-stabilized Ag NPs loaded on th
