Tohoku University · Materials Science
Professor Sang-Kwon Lee's research lab specializes in the design, fabrication, and application of advanced nanomaterials for next-generation electronic, spintronic, and thermoelectric devices. The lab focuses on low-dimensional materials such as GaN nanowires, transition metal dichalcogenides (e.g., WSe₂), and 2D van der Waals heterostructures, with particular emphasis on interface engineering to enhance spin transport, thermoelectric performance, and cellular detection. Key research directions include nanowire-based biosensors for rare cell analysis, spin current enhancement via 2D heterostructures, and high-performance thermoelectric materials with engineered interfaces for energy harvesting.
Figures are computed from collected data and may differ slightly.
We report on the development of a nanowire substrate-enabled laser scanning imaging cytometry for rare cell analysis in order to achieve quantitative, automated, and functional evaluation of circulating tumor cells. Immuno-functionalized nanowire arrays have been demonstrated as a superior material to capture rare cells from heterogeneous cell populations. The laser scanning cytometry method enables large-area, automated quantitation of captured cells and rapid evaluation of functional cellular
Abstract We have studied structural and electrical properties of one dimensionally grown single crystalline gallium nitride (GaN) nanowires (NWs) for nanoscale devices using a metal‐initiated metal‐organic chemical vapor deposition (MOCVD). GaN nanowires were formed via the vapor‐liquid‐solid (VLS) mechanism with gold, iron, or nickel as growth initiators and were found to have triangular cross‐sections with widths of 15 ∼ 200 nm and lengths of 5 ∼ 20 μm. TEM confirmed that the nanowires were si
The Seebeck effect refers to the production of an electric voltage when different temperatures are applied on a conductor, and the corresponding voltage-production efficiency is represented by the Seebeck coefficient. We report a Seebeck effect: thermal generation of driving voltage from the heat flowing in a thin PtSe<sub>2</sub>/PtSe<sub>2</sub> van der Waals homostructure at the interface. We refer to the effect as the interface-induced Seebeck effect. By exploiting this effect by directly at
Recently, significant progress has been made in increasing the figure-of-merit (ZT) of various nanostructured materials, including thin-film and quantum dot superlattice structures. Studies have focused on the size reduction and control of the surface or interface of nanostructured materials since these approaches enhance the thermopower and phonon scattering in quantum and superlattice structures. Currently, bismuth-tellurium-based semiconductor materials are widely employed for thermoelectric
Abstract The spin current is significantly limited by the spin‐orbit interaction strength, material quality, and spin‐mixing conductance at material interfaces. Such limitations lead to spin current decay at the interfaces, which severely hinders potential applications in spin‐current‐generating thermoelectric devices. Thus, methodical studies on the enhancement of spin currents are indispensable. Herein, a novel approach for enhancing the spin current injected into a normal metal, Pt, using int
Recently, low-dimensional superlattice films have attracted significant attention because of their low dimensionality and anisotropic thermoelectric (TE) properties such as the Seebeck coefficient, electrical conductivity, and thermal conductivity. For these superlattice structures, both electrons and phonons show highly anisotropic behavior and exhibit much stronger interface scattering in the out-of-plane direction of the films compared to the in-plane direction. However, no detailed informati
We have successfully investigated the thermal conductivity (κ) of single-crystalline bismuth nanowires (BiNWs) with [110] growth direction, via a straightforward and powerful four-point-probe 3-ω technique in the temperature range 10-280 K. The BiNWs, which are well known as the most effective material for thermoelectric (TE) device applications, were synthesized by compressive thermal stress on a SiO2/Si substrate at 250-270 °C for 10 h. To understand the thermal transport mechanism of BiNWs, w
Two-dimensional (2D) PtSe2 is rapidly emerging as a promising candidate for developing devices that exhibit a significantly enhanced thermoelectric power factor because of its thickness-modulation-induced tunable semiconductor-to-semimetal transition characteristic. This interesting phenomenon motivated us to measure the in-plane Seebeck coefficients and electrical conductivities of large-area 2D PtSe2 thin films with approximately 2–15 nm thicknesses. We observed an outstanding in-plane Seebeck
A large-scale MoS<sub>2</sub> thin film with a holey structure enhances the in-plane Seebeck thermopower, resulting in an enhancement of the Seebeck thermopower anisotropy.
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