Session Index

The research proposal is to heterogeneous growth carbide (SiC) films on silicon (Si) substrates using reactive radio frequency (RF) magnetron sputtering. The substrates are heated to 600℃ to achieve epitaxial growth of SiC films. In order to avoid target damage from heat accumulation, we utilize reactive RF sputtering technique with Si targets and methane (CH4) gas. The bonding properties of SiC films under different RF power levels were analyzed using Raman spectroscopy. The experimental results demonstrate that the RF power of 150W represents the critical point for Si-C bonds and get 4H-SiC crystal after 1200 annealing.

  Preview abstract

This study explores the under-investigated terahertz properties of ultrathin metallic films, specifically electron emission. We observe this emission in ultrathin gold films, driven by a strong THz field. Films of around 2 nm thickness show efficient absorption and significant electron emission. Our analysis, employing Time-of-Flight (TOF) measurements and electron energy distribution fitting, indicates that electron emission is a result of the interaction between hot electrons and the THz electric field.

  Preview abstract

MXene, a new class of 2D materials, is being grad-ually used in energy storage, sensor, catalyst, super-capacitor, and other fields. We also anticipate that MXene can be an enabler in organic-based transistors. Here, we attempt to incorporate titanium carbide Ti3C2Tx MXene into a polythiophene semiconducting layer, in the hope of boosting charge carrier transport. Primary results show a 4-fold enhancement in mobility when 1.0 wt% of MXene is blended. The hybrid tran-sistor also reveals a prolonged air stability with re-spect to pristine polythiophene device.

  Preview abstract

We have fabricated bifacial perovskite solar cells with 10 nm Au/MoS2 and ITO transparent electrodes (TEs) on glass substrates. Compared with the reference device with 100 nm Ag and ITO electrodes, similar PCE values ~ 12 % are observed for the two devices when solar light is irradiated from ITO side. When the solar light illuminates from metal side, only the device with the 10 nm Au/MoS2 TE exhibits similar short-circuit current and PCE value ~ 11.4 %, which have demonstrated the potential of 2D material-assisted nanometer-thick Au films for TE applications in bifacial and tandem solar cells.

  Preview abstract

We examine how thin-film interfacial absorption layers form between Nb2O5 and SiO2. The main aim of this research is to understand the optical properties of the interface, which are crucial for optoelectronic applications. Moreover, we use various target materials to apply anti-reflective coatings and discuss the outcomes obtained from spectroscopy. Overall, this investigation enhances our comprehension of the relationship at the Nb2O5/SiO2 interface.

  Preview abstract

GaN layers were directly epitaxial grown at 600°C using the high power impulse magnetron sputtering technique, in contrast to the MOCVD method that demands temperatures exceeding 1000°C. In this epitaxial process utilizing N2/Ar mixture gas and Ga target, the GaN layers were directly grown on Si (111) substrates and Si (111) substrates with AlN buffer layers. XRD measurements of full-width at half-maximum (FWHM) reveal that the GaN layer with the AlN buffer layer exhibits significantly lower FWHM and stronger intensity. SEM results indicate that the GaN layer deposited on the AlN buffer layer displays a relatively smooth surface.

  Preview abstract

In this work, the optical response and in-plane surface plasmon polariton of a grating prepared by oblique angle deposition of silver is proposed. Based on the P-polarized reflection peak at certain wavelengths. The surface plasmon polariton propagation on the surface of silver coated grating is investigated here. By analyzing the radiation on the surface from a dipole above the surface with FDTD method, the in-plane iso-frequency curves are derived and reveal the anisotropic properties of the grating surface. The results show that the grating surface exhibits anisotropic behavior due to the oblique angle deposition.

  Preview abstract

We report a custom-built frequency domain fluorescence lifetime instrument, which enables fluorescence lifetime measurement of fluorophore species at various modulation frequencies (200kHz-30MHz). Fluorescence excitation is carried out by light-emitting diodes (LEDs), and frequency output of the excitation light source and photomultiplier tube (PMT) is directly controlled by programmable logic gate array (FPGA). With this system, we measured and analyzed fluorescence lifetimes of CsPbBr3 at different concentrations.

  Preview abstract