Bulletin of the American Physical Society
Joint Fall 2017 Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 62, Number 16
Friday–Saturday, October 20–21, 2017; The University of Texas at Dallas, Richardson, Texas
Session K3: Materials Science II |
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Chair: Bing Lv, University of Texas at Dallas Room: DGAC 1.102C |
Saturday, October 21, 2017 10:30AM - 10:42AM |
K3.00001: Modulation of Photoluminescence of Monolayer MoS$_{\mathrm{2}}$ Zhenrong Zhang, Blake Birmingham, Jiantan Yuan, Matthias Filez Filez, Donglong Fu, Jun Lou, Jonathan Hu, Bert Weckhuysen Modulation of photoluminescence (PL) of two-dimensional materials is important for its optoelectronic and catalysis applications. We have systematically studied the effect of thermal and photo-reaction of various ambient molecules (H$_{\mathrm{2}}$O, O$_{\mathrm{2}}$, and N$_{\mathrm{2}})$ on the photoluminescence of CVD grown monolayer MoS$_{\mathrm{2}}$. The results show that the photoreaction of the O$_{\mathrm{2}}$ with MoS$_{\mathrm{2}}$ monolayer can affect the PL intensity. For the application of desulfurization of gasoline, we compared the difference in the interaction of pyridine molecules with monolayer MoS$_{\mathrm{2}}$. Our results show that liquid pyridine and gaseous pyridine interact differently with MoS$_{\mathrm{2}}$ monolayers. [Preview Abstract] |
Saturday, October 21, 2017 10:42AM - 10:54AM |
K3.00002: Magneto-Optical Faraday Effect in NiO and NiFeO Thin Films Brian Collier, Wilhelmus Geerts, Ahad Talukder, James Nick Talbert, Aaron Medina, Andres Oliva Recently, Resistive Random-Access Memory (RRAM) has been the focus of research due to its high bit density as a possible replacement for flash memory. The switching characteristics of RRAM give rise to curiosity of the possible use of metal oxides, such as NiO and iron doped NiO, for use in RRAM devices. In the low resistance state, large oxygen-vacancy-clusters may be magnetic and provide a low resistive path for electrons, therefore we investigated the magneto-optical properties of reactive RF-sputtered NiO and NiFeO thin films. Samples were sputtered with oxygen flow rates of 1{\%} and 10{\%} on fused quartz and microscopic glass slides and were characterized using the magneto-optical Faraday effect. This technique measures the rotation of polarized light in transmission mode as a function of an applied magnetic field. The high sensitivity of this method makes it ideal for characterization of the magnetic properties of thin film materials to detect possible magnetic regions in the films. The Faraday rotation was used to calculate the Verdet constant for each sample. Measurement results indicate that doping of Fe as well as sputtering at a low (1{\%}) oxygen flow rate correlate with a higher Verdet constant. [Preview Abstract] |
Saturday, October 21, 2017 10:54AM - 11:06AM |
K3.00003: Photogenerated charge transfer between conducting polymer and oxide L.N.S. Murthy, L. Xu, T.B Daunis, J.W.P Hsu, F.Y Cao, Y.J Cheng Sensitized photodetectors separate the photon detection from electrical signal processing and can broaden the spectral range on the same detection platform. Here, we study a sensitized phototransistor with n-type oxides (InO$_{\mathrm{x}}$, ZnO) as the channel layer and polymers (P3HT, PFBT$_{\mathrm{2}}$Se$_{\mathrm{2}}$Th) as the absorber. The transfer of photogenerated charges from the absorber to the channel is critical for the functioning of these devices. Magnitude of surface photovoltage (SPV), change in the Fermi level with illumination, reflects the efficiency of the charge transfer, and its spectrum shows the detectable energy range. We confirm that the spectrum is determined by the absorber; hence SPV spectrum is similar for P3HT/InO$_{\mathrm{x}}$ and P3HT/ZnO, and is larger using PFBT$_{\mathrm{2}}$Se$_{\mathrm{2}}$Th/InO$_{\mathrm{x}}$ than P3HT/InO$_{\mathrm{x}}$ because PFBT$_{\mathrm{2}}$Se$_{\mathrm{2}}$Th has a smaller bandgap. We find the magnitude of SPV is larger in P3HT/InO$_{\mathrm{x}}$ compared with PFBT$_{\mathrm{2}}$Se$_{\mathrm{2}}$Th/InO$_{\mathrm{x}}$ and larger even in P3HT/ZnO. The recombination time of photogenerated charges are studied by making bilayer devices with top electrodes. The insight gained in these studies is critical for realization of sensitized phototransistors. [Preview Abstract] |
Saturday, October 21, 2017 11:06AM - 11:18AM |
K3.00004: All-Oxide Ga$_{\mathrm{2}}$O$_{\mathrm{3}}$-NiO$_{\mathrm{x}}$ PN Junction Diodes Enabled by Tunable Electrical and Optical Properties of Nickel Oxide (NiO$_{\mathrm{x}})$ and Gallium Oxide (Ga$_{\mathrm{2}}$O$_{\mathrm{3}})$ Thin Films Deposited by Pulsed Laser Deposition at Room Temperature Maria Isabel Pintor Monroy, Bayron Lennin Murillo-Borjas, Diego Barrera, Julia W.P. Hsu, Husam N. Alshareef, Manuel A. Quevedo-Lopez The need of stable, high quality electronic devices such as pn junctions, light-emitting diodes, transistors and UV photodetectors has pushed the development of both, p- and n-type, transparent semiconductor oxides. Thin films heterojunctions have been reported using ZnO and IGZO as n-type and NiO as p-type, with at least one metallic contact. Pulsed laser deposition (PLD) offers advantages over other deposition methods as more homogeneous, smoother surfaces with high reproducibility. In this work we present a new all-oxide heterojunction based in oxides deposited by PLD at room temperature without heat treatment. This heterojunction has low leakage current, an ideality factor close to 2,10$^{\mathrm{5}}$ on/off ratio and acceptable on-voltage, with a wide band gap which makes it even more interesting for optoelectronics applications. Temperature dependence on the device performance is also discussed. [Preview Abstract] |
Saturday, October 21, 2017 11:18AM - 11:30AM |
K3.00005: Large crystal growth, physical properties, and doping studies of SnSe2 Hanlin Wu, Sheng Li, Bing Lv Two dimensional (2D) layered metal dichalcogenides, exhibiting diverse physical properties in charge-density-wave (CDW), superconductivity (SC), topology, and thermoelectrics, are attracting great attention in the past few years. In this presentation, we will primarily focus on CdI$_{\mathrm{2}}$-type SnSe$_{\mathrm{2.\thinspace }}$We have successfully grown high quality large size single crystals up to several centimeters using modified Bridgman technique, and carried out systematical doping studies on the SnSe$_{\mathrm{2}}$ crystal through chemical interactions. The resulting physical properties of the grown crystals and intercalated samples will be presented. The potential high thermoelectric properties and superconductivity will also be discussed. [Preview Abstract] |
Saturday, October 21, 2017 11:30AM - 11:42AM |
K3.00006: Fabrication and Structural - Optical Characterization of BTO : MAPbX Nanocomposites for Solar Cell Applications Daniel Morales, Chaminda Hettiarachchi Organo lead halide perovskites, specifically methylammonium lead iodide chloride, (CH 3 NH 3 PbI 3-x Cl x ) has potential of becoming the leading solar cell technology with its rapidly rising efficiencies and simple, low-cost fabrication methods. Ferroelectrics can be exploited to reduce bimolecular recombination because spontaneous electric polarization associated local internal electric fields can be used to reduce charge carrier recombination. Barium Titanate (BaTiO3 -BTO) is a well-known ferroelectric material. In this work, we explore structural and optical properties of CH 3 NH 3 PbI 3-x Cl x perovskite and ferroelectric BTO nanocomposite thin films fabricated via the process of Aerosol Assisted Chemical Vapor Deposition (AACVD). Structural and optical measurements show as BTO concentration increases in the composite thin films, the crystallinity and optical absorption of composite thin films decrease. The grain size of perovskite in the composite decreases as well. Structural and optical characterization of CH 3 NH 3 PbI 3-x Cl x : BTO nanocomposites fabricated at different BTO nanoparticle concentrations will be presented. [Preview Abstract] |
Saturday, October 21, 2017 11:42AM - 11:54AM |
K3.00007: Hexagonal boron nitride particles for determining the thermal conductivity of diamond films based on near-ultraviolet micro-Raman mapping Brian Squires, B Logan Hancock, Mohammad Nazari, Jonathan Anderson, Edwin Piner, Mark Holtz Studies are reported of the thermal conductivity ($\kappa )$ for a suspended \textasciitilde 1 \textmu m thick diamond membrane. Near-ultraviolet micro-Raman spectroscopy is used to map the temperature rise produced in the diamond by a micro-fabricated heater and in hexagonal boron nitride micro/ nano-particles which are dispersed on the surface as local temperature sensors independent of thermal stress in the diamond. Thermal conductivity is determined analytically from Raman temperature rise and also by fitting data via simulation, using a Monte Carlo optimization approach. The low value obtained for $\kappa $, ${78.4}_{-5.1}^{+8.6}$~~W m$^{\mathrm{-1\thinspace }}$K$^{\mathrm{-1}}$, is attributed to the nanocrystalline diamond grain structure as analyzed by transmission electron microscopy (TEM). TEM identifies a disordered silicon-carbon interfacial layer \textasciitilde 2 nm thick which is expected to affect the diamond/silicon thermal boundary resistance. [Preview Abstract] |
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