2D Gallium Sulfide-Based 1D Photonic Crystal Biosensor for Glucose Concentration Detection.

Unidimensional photonic crystal-based biosensors have gained much attention in the area of blood glucose measurement. In this paper, we propose two novel designs based on two-dimensional (2D) Van der Waals materials. The first 1D photonic crystal design consists of multilayers of 2D gallium sulfide and 2D muscovite mica [GaS/Mica]D[GaS/Mica], and the second design consists of multilayers of 2D gallium sulfide [GaS/G]D[GaS/G].

Photovoltaic Characteristics of GaSe/MoSe Heterojunction Devices.

The two-dimensional materials have the thickness of an atomic layer level and are expected as alternative materials for future electronics and optoelectronics due to their specific properties. Especially recently, transition metal monochalcogenides and dichalcogenides have attracted attention. Since these materials have a band gap unlike graphene and exhibit a semiconductor property even in a single layer, application to a new flexible optoelectronics is expected.

Micro-Hall Sensors Based on Two-Dimensional Molybdenum Diselenide.

Sensors and electronic devices based on semiconductors in their two-dimensional forms have many advantages. In this paper, we studied micro-Hall sensors based on two-dimensional molybdenum diselenide for the first time. The micro-Hall sensor based on a Ti/MoSe₂/Ti structure clearly showed a linear dependence of the Hall voltage as a function of the magnetic field, with a magnetic sensitivity of ∼16 V/AT.

Effects of Rapid Thermal Treatment on Characteristics of Magnetron-Sputtered NiO Thin Films for Supercapacitor Applications.

Supercapacitors are promising energy storage devices due to their high power density, long cycling life, and short charging time. NiO is one of the alternative inorganic materials that could be used to replace the conventional RuO2 electrodes in these supercapacitors. In the present study, NiO thin film was prepared by radio frequency magnetron sputtering using a NiO alloy target.

Thickness dependence on the optoelectronic properties of multilayered GaSe based photodetector.

Two-dimensional (2D) layered materials exhibit unique optoelectronic properties at atomic thicknesses. In this paper, we fabricated metal-semiconductor-metal based photodetectors using layered gallium selenide (GaSe) with different thicknesses. The electrical and optoelectronic properties of the photodetectors were studied, and these devices showed good electrical characteristics down to GaSe flake thicknesses of 30 nm.

Laser Power Dependent Optical Properties of Mono- and Few-Layer MoS2.

We report on the exponential decay of the red-shift of the photoluminescence A-exciton peak in monolayer molybdenum disulfide (MoS2) with the excitation laser power. The linear relationship found for the thermal variation of the same peak suggests that the laser power effect goes beyond the exciton dynamics associated to temperature variations. Laser exitation power effect on the broadening and red-shifting of the A(1g) and E(2g)1 phonon peaks observed by Raman spectroscopy reflect the damping of vibration due local thermal heating induced by the laser.

Magnetic-particle-sensing based diagnostic protocols and applications.

Magnetic particle-labeled biomaterial detection has attracted much attention in recent years for a number of reasons; easy manipulation by external magnetic fields, easy functionalization of the surface, and large surface-to-volume ratio, to name but a few. In this review, we report on our recent investigations into the detection of nano-sized magnetic particles. First, the detection by Hall magnetic sensor with lock-in amplifier and alternative magnetic field is summarized.

Radical-assisted chemical doping for chemically derived graphene.

Carrier doping of graphene is one of the most challenging issues that needs to be solved to enable its use in various applications. We developed a carrier doping method using radical-assisted conjugated organic molecules in the liquid phase and demonstrated all-wet fabrication process of doped graphene films without any vacuum process. Charge transfer interaction between graphene and dopant molecules was directly investigated by spectroscopic studies.

Porous silicon platform for optical detection of functionalized magnetic particles biosensing.

The physical properties of porous materials are being exploited for a wide range of applications including optical biosensors, waveguides, gas sensors, micro capacitors, and solar cells. Here, we review the fast, easy and inexpensive electrochemical anodization based fabrication porous silicon (PSi) for optical biosensing using functionalized magnetic particles. Combining magnetically labeled biomolecules with PSi offers a rapid and one-step immunoassay and real-time detection by magnetic manipulation of superparamagnetic beads (SPBs) functionalized with target molecules onto corresponding probe molecules immobilized inside nano-pores of PSi.