Ex) Article Title, Author, Keywords
Ex) Article Title, Author, Keywords
Abstract : A new silicon chip (INVESTIGATOR) manufactured for R\&D purposes has 134 mini-matrices with various pixel designs. Each matrix consists of 8 $\times$ 8 pixels, which put out 64 analogue signals at 65 MHz. The silicon pixel design is based on the newest technology of the complementary metal-oxide-semiconductor (CMOS) monolithic active pixel sensor (MAPS), which integrates the silicon sensor and the read-out circuitry in a pixel. The MAPS has advantages of low power consumption, high granularity of a pixel, and fast read-out. In this paper, the charge collection time for different pixel designs and reverse bias voltages is studied by using the INVESTIGATOR. The charge collection time is estimated by fitting the waveform for changing pixel pitch, reverse bias voltage, diameter of collection n-well diode, and spacing. Based on these results, we discuss the dependence of the relative depletion volume and the charge collection time on the pixel geometry.
Abstract : We analyzed experimental data on elastic $\alpha$ + $^{116}$Sn and $^{6}$Li + $^{116}$Sn scatterings at $E_{lab}=$ 240 MeV within the framework of the Coulomb-modified Glauber model. The ingredients of the model used in this work were the nucleon-nucleon ($NN)$ amplitude and the densities of the colliding nuclei. The calculations included the effective $NN $ amplitude considering a $q^{4}$ component and the surface-matched Gaussian density of the target nucleus. The calculated results reproduced satisfactorily the structures of differential cross sections and agreed well with the experimental data. \ The oscillatory structures observed in the angular distributions were explained using the strong interference between the near-side and the far-side scattering amplitudes. We found that the introduction of both an effective $NN$ amplitude and a surface-matched Gaussian density plays an important role in providing a better description of the elastic data.
Abstract : The effects of partial substitution of nitrate groups at the SO$_{4}$ sites on the superconducting properties of the TlSr$_{4}$Cu$_{2}$O$_{z}$(SO$_{4}$)$_{1-x}$(NO$_{3}$)$_{x}$ system have been investigated. X-ray diffraction data showed that the solubility limit of (NO$_{3}$) was about $x$ = 0.35. The change in the solubility limit of oxyanion for sulfate was discussed in connection with the characteristics of the oxyanion species. Within the solubility limit, the introduction of the nitrate groups did not change significantly the transition temperature of the pristine TlSr$_{4}$Cu$_{2}$O$_{z}$(SO$_{4}$) compound. However, we found that compared to the pristine compound, the introduction of the nitrate groups degraded the stability properties of the sample after annealing at 400$^{\circ}$C in Ar atmosphere.
Abstract : Due to the energy gaps of copper from 2.1 to 2.7 eV, its high light absorption, its nontoxicity and its abundance on the earth, Cu$_{2}$O is an attractive material for use in various areas such as photovoltaic power generation, photocatalytic reactions, water photolysis, nonlinear optics, and gas sensing. Many researches efforts are being conducted to obtain high-quality Cu$_{2}$O thin films. In this study, high-quality, epitaxial Cu$_{2}$O (111) thin films were obtained via a relatively simple method, rapid thermal processes at high temperature of RF sputtered Cu (111) thin film on a sapphire substrate. XRD, SEM and UV-Vis spectroscopy measurements confirmed the high crystallinity of the Cu$_{2}$O (111) thin film oxidized for 30 minutes at a temperature of 800 $^{\circ}$C under an atmosphere of argon with 3 ppm of oxygen. Also, because of the high crystal-quality of the Cu$_{2}$O (111) thin films, blue and indigo energy gaps at room temperature were obtained from the absorption coefficient $\alpha$. The obtained energy band gaps are consistent with the theoretical values obtained from Cu$_{2}$O bulk structures.
Abstract : MAPbX$_3$, is an organic-inorganic perovskite material system which can be applied in various areas such as magneto-optical data storage, solar cells, lasers, LEDs, etc. MAPbI$_3$ and MAPbBr$_3$ are known to undergo a cubic-to-tetragonal transition at temperatures of about 327 K and 220 K and a tetragonal-to-orthorhombic transition at about 150 K and 145 K, respectively. The transmittance spectra of pallet samples are measured in the far-infrared (FIR) region at various temperatures from room temperature to 80 K by using a Fourier transform infrared (FTIR) spectroscopy-type Bruker Vertex 80v spectrometer. The absorption coefficients are obtained and fitted by using the Drude-Lorentz model to obtain other optical constants including the electric permittivity, optical conductivity, and extinction coefficient. Then, the optical conductivity is fitted to obtain the position and damping coefficient of the longitudinal optical (LO) and the transverse optical (TO) phonons for the sample materials, which are used to calculate the electron-phonon coupling constants, polaron mass, and polaron radii.
Jong-Ho PARK*
New Phys.: Sae Mulli 2019; 69(1): 1-15
https://doi.org/10.3938/NPSM.69.1
Seong-Wook PARK, Hoon-Hyun CHO, Dong-Sun YOO, Il-Gon KIM*
New Phys.: Sae Mulli 2019; 69(1): 16-24
https://doi.org/10.3938/NPSM.69.16
Vasanthan DEVARAJ, Jong-Min LEE, Chun Tae KIM, Won-Geun KIM, Jin-Woo OH*
New Phys.: Sae Mulli 2019; 69(1): 25-30
https://doi.org/10.3938/NPSM.69.25