• Bulletin of the Korean Chemical Society
• /
• v.21 no.1
• /
• pp.9-22
• /
• 2000

Optical-optical double resonance experiments have been used to identify and characterize five ion-pair states and several of the bound and repulsive valence states of ClF. This report provides a description of these experiments for $^{35}CIF$ and $^{37}CIF$, and a summary of the current knowledge of the valence and ion-pair states. The important role of perturbations among the rovibronic levels of the bound valence states and their utilization in the double resonance technique is discussed. The ion-pair states of the same symmetry, ${\Omega}$=$0^+$ (E and f) and 1( $\beta$ and G) interact very strongly and the spectroscopy of these states is anomalous and, hence, interesting. Comparison is made to some recent ab initio calculations for ClF. One possible explanation of the irregular vibrational energy levels and rotational constants of the ion-pair states of $O^+$ and 1 symmetry is a crossing of the diabatic potentials of these states. Some currently unresolved questions about ClF spectroscopy are posed for future work. Where appropriate, analogy is made between the electronic states of ClF and the corresponding valence and ion-pair states of $Cl_2.$.

• Journal of Korean Vacuum Science & Technology
• /
• v.3 no.2
• /
• pp.112-115
• /
• 1999

The real ($\varepsilon$1) and imaginary ($\varepsilon$2) parts of the dielectric function of ZnS have been measured by spectroscopic ellipsometry (SE) in the 3.7-6.0 eV photon-energy range at room temperature. The obtained dielectric function spectra reveal distinct structures at energies E0/(E0+$\Delta$0) and E1 critical points. The spectrum after chemical treatment to remove surface oxide overlayer showed that these data seem to be the best representation of the dielectric function of ZnS, having the largest $\varepsilon$2 value at E1 peak region reported so far by SE. Dielectric-related optical constants of ZnS, such as the complex refractive indices (n+n=ik), absorption coefficient, and reflectance, are also presented.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.5
• /
• pp.877-886
• /
• 2019

The energy band gaps and optical constants of zincblende $In_yGa_{1-y}As_{1-x}N_x$ on the variation of temperature and composition are determined by using band anticrossing method. The energy band gaps are decreasing continuously in $In_yGa_{1-y}As_{1-x}N_x$ ($0{\leq}x{\leq}0.05$, $0{\leq}y{\leq}1.0$, 300K) and the bowing parameter is calculated as 0.522eV. The calculation results of energy band gaps are consistent with those of other studies. A refractive index n and a high-frequency dielectric constant ${\varepsilon}$ are calculated by a proposed modeling equation using the results of energy band gaps.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.2
• /
• pp.87-95
• /
• 1996

We have studied the effects of La concentration on the optical and electrical properties of lead lanthanum titanate (PLT) thin films by using sol-gel method. Both the optical and electrical properties are greatly affected by the La concentration. The refreactiv eindices of the films varied from 2.23 to 1.93 with varying La concentration in the range from 15 to 33 mol%. The dielectric constants of the films vary form 340 to 870 with varying La concentration in the range form 15 to 33 mol%. Hysteresis loop becomes slimmer with the increase of La concentration form 15 to 28mol% and little fatter again with the increase of La concentration form 28 to 33 mol%. Among the films investigated in this research, PLT(28) thin film shows the best dielectric properties for the application to the dielectrics of ULSI DRAM's. At the frequency of 100Hz, the dielectric constant and the loss tangent of PLT(28) thin films are 940 and 0.08 respectively. Its leakage current density at 1.5${\times}10^{5}$V/cm is 1${\times}10^{-6}A/cm^{2}$. The comparision between the simulated and the experimental curves for the switching transient characteristics shows that PLT (28) thin films behaves like normal dielectrics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.11
• /
• pp.969-974
• /
• 2003

HgGa$_2$S$_4$ single crystals were grown by the chemical transport reaction method. The HgGa$_2$S$_4$ single crystal crystallized into a defect chalcopyrite structure (I 4). The lattice constants of the single crystal were found to be a = 5.635 $\AA$ and c = 10.473 $\AA$. The direct and indirect optical energy gaps were found to be 2.84eV and 2.78eV, respectively. Photoluminescence peaks of HgGa$_2$S$_4$ single crystal were observed at 2.37 eV, 2.18 eV, and 1.81 eV. In the single crystal, the donor level of 0.25 eV, the acceptor levels of 0.97 eV and 0.41 eV were obtained by TSC, PICTS, and absorption measurements. The photoluminescence peaks were analyzed to relate to the indirect conduction band, the donor level, and the acceptor levels.

• Journal of the Optical Society of Korea
• /
• v.12 no.2
• /
• pp.112-117
• /
• 2008

Single-mode propagation conditions of X-ray waveguides are investigated by numerical calculations in order to understand the importance of waveguide design parameters, such as core thickness and the optical constants of waveguide materials, on the transmission and coherence properties of the waveguide. The simulation code for mode analyzing is developed based on a numerical solution of the parabolic wave equation. The initial boundary value problem is solved numerically using a finite-difference scheme based on the Crank-Nicolson scheme. The E-field intensities in a core layer are calculated at an X-ray energy of 8.0 keV for air and beryllium(Be) core waveguides with different cladding layers such as Pt, Au, W, Ni and Si to determine the dependence on waveguide materials. The highest E-field intensity radiated at the exit of the waveguide is obtained from the Pt cladded beryllium core with a thickness of 20 nm. However, the intensity from the air core waveguide with Pt cladding reaches 64% of the Be-Pt waveguide. The dependence on the core thickness, which is the major parameter used to generate a single mode in the waveguide, is investigated for the air-Pt, and Be-Pt waveguides at an X-ray energy of 8.0 keV. The mode profiles at the exit are shown for the single mode at a thickness of up to 20 nm for the air-Pt and the Be-Pt waveguides.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.05c
• /
• pp.47-52
• /
• 2004

$HgGa_2S_4$ single crystals were grown by the chemical transport reaction method. The $HgGa_2S_4$ single crystal crystallized into a defect chalcopyrite structure $(I\bar{4})$. The lattice constants of the single crystal were found to be a=5.635 ${\AA}$ and c=10.473 ${\AA}$. The direct and indirect optical energy gaps were found to be 2.84 eV and 2.78 eV, respectively. Photoluminescence peaks of $HgGa_2S_4$ single crystal were observed at 2.37 eV, 2.18 eV, and 1.81 eV. In the single crystal, the donor level of 0.25 eV, the acceptor levels of 0.97 eV and 0.41 eV were obtained by TSC, PICTS, and absorption measurements. The photoluminescence peaks were analyzed to relate to the indirect conduction band, the donor level, and the acceptor levels.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.1
• /
• pp.61-66
• /
• 2002

A method for designing antireflection (AR) and antistatic (AS) coating layer by the use of conducting polymer as an electrically conductive transparent layer is proposed. The conducting AR coating is composed of four-layer with alternating high and low refractive index layer: silicon dioxide (n=1.44) and titanium dioxide (n=2.02) prepared at low temperature by sol-gel method are used as the low and high refractive index layer, respectively. The poly(3,4-ethylenedioxythiophene) which has the surface resistivity of 10$^4$Ω/$\square$ is used as a conductive layer. Optical constant of each ARAS coating layers such as refractive index and optical thickness were measured by 7he spectroscopic ellipsometer and from the measured optical constants the spectral properties such as reflectance and transmittance were simulated in the risible region. The reflectance of ARAS films on glass substrate was below 1 %R and the transmittance was higher than 95 % in the visible wavelength (400-700 nm). The measured AR spectral properties was very similar to its simulated results.

• Korean Journal of Optics and Photonics
• /
• v.32 no.4
• /
• pp.172-179
• /
• 2021

A near-normal-incidence ellipsometer (NNIE) is suggested as an optical critical dimension (OCD) measurement system that is highly sensitive to the bottom defect of a sample with high-aspect-ratio structured patterns. Incident light passes through a polarizer and a phase retarder in sequence, and the reflected light from the sample also passes through them, but in reverse order. The operating principle of this NNIE, where a single polarizer and a single phase retarder are shared by the incident and reflected light, is studied, and a method to determine the ellipsometric constants from the measured intensities at proper combinations of the azimuthal angles of polarizer and retarder is presented.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.1205-1211
• /
• 2013

The structural and optical properties of the ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO nanorods were investigated using field-emission scanning electron microscopy, X-ray diffraction, photoluminescence (PL) and ultraviolet-visible spectroscopy. All the nanorods grew with good alignment on the ZnO seed layers and the ZnO nanorod dimensions could be controlled by the addition of the various dopants. For instance, the diameter of the nanorods decreased with increasing atomic number of the dopants. The ratio between the near-band-edge emission (NBE) and the deep-level emission (DLE) intensities ($I_{NBE}/I_{DLE}$) obtained by PL gradually decreased because the DLE intensity from the nanorods gradually increased with increase in the atomic number of the dopants. We found that the dopants affected the structural and optical properties of the ZnO nanorods including their dimensions, lattice constants, residual stresses, bond lengths, PL properties, transmittance values, optical band gaps, and Urbach energies.