Recent Developments in Biological, Structural and Functional Thin Films and Coatings: Functional Surfaces and Thin Films I
Sponsored by: TMS Functional Materials Division, TMS: Thin Films and Interfaces Committee
Program Organizers: Adele Carradň, Université de Strasbourg IPCMS; Nancy Michael, University of Texas at Arlington; Ramana Chintalapalle, UTEP; Heinz Palkowski, Clausthal Univ of Technology; Vikas Tomar, Purdue Univ; Nuggehalli Ravindra, NJIT

Tuesday 8:30 AM
February 28, 2017
Room: Pacific 18
Location: Marriott Marquis Hotel

Session Chair: Nancy Michael, University of Texas at Arlington; Ramana Chintalapalle, University of Texas at El Paso, UTEP

8:30 AM  Invited
Silicon Doped Nanoparticles Embedded in Transparent Oxide Thin Films for Micro-optoelectronic Devices: Gerald Ferblantier1; Fabien Ehrhardt1; Corine Ulhaq-Bouillet2; Dominique Muller1; Daniel Mathiot1; 1ICube Laboratory; 2IPCMS
    In this work we present a way to obtain silicon nanoparticles embedded in doped dielectric thin films. For the fabrication we used plasma enhanced chemical vapor deposition technique and ion implantation technique. In order to form silicon nanoparticles, thin films were heated at high temperature. The nanoparticles crystalline structure and size were assessed by energy filtered transmission electron microscopy technique. The distribution profile of the dopant elements within the host matrix was determined by the Rutherford backscattering spectroscopy method. The energy dispersive X-ray mapping, coupled with spectrum imaging on silicon plasmon, was performed to localize the dopant impurities versus the nanoparticles. Different behaviours were observed following the implanted dopant elements. Experimentally, we showed that phosphorus and arsenic dopant atoms were inserted in silicon nanoparticles. On the opposite, boron dopant atoms were localized around the nanoparticles. This could be interesting for electronic devices such as sensors using surface plasmon resonance.

8:50 AM  Invited
Nanoscale Structure-property Relationship Studies of Metallic and Oxide Thin Films Using Correlative Electron Microscopy and Atom Probe Tomography: Arun Devaraj1; Steven Spurgeon1; Rama Vemuri1; Richard Oleksak2; Greg Herman2; Scott Chambers1; Charles Henager1; Aashish Rohatgi1; Thevuthasan Suntharampillai1; 1Pacific Northwest National Laboratory; 2Oregon State University
    Metallic and oxide thin films are used for a variety of structural and functional applications. The microstructure of such thin films directly determine the properties and hence influence the ultimate performance during use. The structural or compositional heterogeneity of such thin films are often in the nano-dimensions making it extremely challenging to quantify accurately by using conventional large spot size analytical methods. Advanced high spatial resolution methods like correlative electron microscopy and atom probe tomography are uniquely powerful in analyzing compositional and structural heterogeneity in thin films of metals and oxides, aiding in obtaining new insights on structure-property relationships. In this talk, examples for such detailed structure-property relationship studies from metallic thin film systems including Al alloy thin films, Ta-Ni-Si amorphous thin films, Ti/Al multilayer thin films and epitaxial double perovskite La2MnNiO6 oxide thin film will be presented.

9:15 AM  
Influence of MgF2 Protective Coating on Plasmonic Response of Mg Thin Films: Richard Laroche1; Kanagasundar Appusamy1; Steve Blair1; Ajay Nahata1; Sivaraman Guruswamy1; 1University of Utah
    Magnesium thin films have shown promising results for UV plasmonic applications, but magnesium suffers from severe surface oxidation, which inhibits its plasmonic response. In this presentation, the effect of protective coatings like magnesium fluoride (MgF2) on preventing oxidation as well as optical response of Mg is examined. MgF2 was chosen as the protective coating because of its transparency in the UV. Various thicknesses of MgF2 are studied, and the corresponding optical constants are obtained through ellipsometry measurements. The structure of MgF2 is examined using x-ray diffraction (XRD), the chemical composition is determined with X-ray photoelectron spectroscopy (XPS), and surface topography is examined with atomic force microscopy (AFM) and scanning electron microscopy (SEM).

9:35 AM  Cancelled
Advanced Characterization of Metal Nitride Thin Films Using Spherical Aberration Corrected TEM: Zaoli Zhang1; 1Erich Schmid Institute of Materials Science, Austrian Academy of Sciences
    Transition metal nitrides have found wide-spread applications in the cutting- and machining-tool industry due to their extreme hardness, thermal stability and resistance to corrosion. The increasing demand of these nitrides requires an in-depth understanding of their structures at the atomic level. This has led to numerous experimental and theoretical researches. Here, some recent results on the atomic and electronic structures of metal nitride thin films (CrN, VN and TiN) on MgO and Al2O3 substrate using advanced CS-corrected TEM and theoretical calculations will be reported. By a combination of HRTEM image analysis, such as atomic displacement using geometrical phase analysis, and spectrum analysis, for instance examining the low-loss, core-loss, and fine structures, some generalized conclusions have been made. A relationship between electronic structure change and elastic deformation has been experimentally derived, revealing that the elastic deformation may lead to a noticeable change in the electronic structures.

9:55 AM Break

10:15 AM  Invited
Moth Eye-based, Graded Index Surface Treatments to Control Reflection: Lesley Chan1; Chris Pynn1; Dan Morse1; Michael Gordon1; 1UCSB
    This talk will highlight our recent work on bio-inspired surface treatments to control reflection at interfaces. An easy, scalable and defect-tolerant surface modification protocol, based on colloidal lithography and plasma etching, was developed to create synthetic 'moth-eye' (ME) anti-reflective structures in different material platforms for photonics and energy applications. Large increases in transmission, bandwidth, and omni-directional response were obtained in Si, Ge, GaAs, and CdTe platforms for IR (2-50+ microns), with performance better than commercial, interference-based coatings. ME coatings were also implemented in blue-green InGaN/GaN quantum well LED structures to enhance light extraction and device efficiency. Effective medium theory, finite difference time domain (FDTD) simulations, and quantitative measurements of transmission, reflection and diffuse scattering were used to understand the ‘photon balance’ of moth-eye films to investigate how optical behavior depends on moth-eye geometry, (dis)order, and pattern fidelity.

10:40 AM  
Nitrogen Incorporation Induced Tuning of the Optical Properties of Niobium Oxide Thin Films: Oscar Nunez1; Neil Murphy2; Chintalapalle Ramana1; 1The University of Texas at El Paso; 2Air Force Research Laboratory
    While Nb2O5 is insulating, optical properties can be tuned by selectively doping with nitrogen. Amorphous niobium oxynitride (Nb-O-N) thin films were produced under variable nitrogen flow rates. The effect of reactive nitrogen content on the surface chemistry and electronic structure is studied in detail. Compositional changes were significant as a function of QN2, which resulted in the systematic alteration of electrical, optical and mechanical properties. XPS and RBS measurements indicated that nitrogen incorporation for Nb-O-N films did not take place in samples deposited with ≤ 6 sccm QN2. Films without nitrogen content displayed optical properties indicative of insulating Nb2O5, with band gap (Eg) results of ~ 3.5 eV from spectrophotometry and ellipsometry experiments. Nitrogen incorporation caused semiconducting and metallic-like behavior with low Eg values of ~ 2.0 eV and high electrical conductivity values up to 2.3x105 Sm-1. Results will be discussed to establish a structure-property-processing relationship in Nb-O-N optical coatings.

11:00 AM  
High Stacking-Fault Energy Nanotwinned Materials: Joel Bahena1; Leonardo Velasco1; Andrea Hodge1; 1University of Southern California
    Nanotwinned (nt) materials have shown improved mechanical properties, thermal stability, and corrosion resistance when compared to their ultrafine-grained and nanocrsytalline counterparts. To date, most studies of nt materials have focused on low stacking fault energy (SFE) metals, since the probability of twin formation decreases with increasing SFE. Therefore, twin formation in high SFE materials has not been thoroughly explored, limiting the potential applications. In this study, twin formation in several high SFE materials were explored through the synthesis of thin films by DC magnetron sputtering. The microstructures of the sputtered samples were characterized by TEM and FIB. Through the manipulation of the deposition parameters nanotwinned structures were observed in pure Al (SFE=166 mJ/m^2), Al-Mg alloys (SFE≤166mJ/m^2), and pure Ni (SFE=125 mJ/m^2) sputtered films.

11:20 AM  
Synthesis of Self-cleaning, Multi-functional Metal Oxide Coatings by the Atmospheric Pressure Plasma Technique: Wei-Chen Hung1; Ching-Yu Yang2; Po-Yu Chen2; 1National Tsing Hua University ; 2National Tsing Hua University
    Self-cleaning coatings have been developed for decades and led to wide applications yet still limited by the expensive and complex processes. In this study, a novel method was used to synthesize mechanically/thermally robust self-cleaning surfaces. The atmospheric pressure plasma technique was utilized to active the substrate surface and created stalagmite-like, hierarchical-structured metal-oxide coatings in a few seconds. The parameters of working power, oxygen flow rate, coating time were evaluated and optimized. After silanization, tungsten oxide coatings exhibit superhydrophobicity and oleophobicity with low sliding angle and self-cleaning capability. Water streaming, sand abrasion tests as well as elevated temperature evaluation were conducted and results showed good mechanical durability and long-term thermal stability. Titanium oxide coatings were also synthesized and post-treated, which demonstrated photocatalytic ability and UV-generated superhydrophilic phenomenon. We developed a facile and cost-effective method to fabricate multifunctional surfaces which could be applied to various substrates in different fields.

11:40 AM  
Ultra-Fast Boronizing of Low Carbon Steel Compared With Chromium Carbide Hard Facing Steel Grades: Bakr Rabeeh1; Yasser Fouad1; Zeyad Abd El Azim1; 1German University in Cairo, GUC
    Coating is one of the recent demand for the enhancement of wear resistance and mechanical performance of structural materials. Chromium carbide hard-facing alloys of hypo- and hype- eutectic steel grades and ultra-fast boronizing of low carbon steel are compared. The first illustrates, the abrasion resistance and mechanical performance of three selected hard-facing alloy grades reinforced with primary chromium carbides. The second illustrates, ultra-fast surface coating and hardening of low carbon steel via the application powder-pack boriding process in a hot isostatic pressing. Low carbon steel sample packed with boric acid and borax, heated at 1050oC for 30 minutes and then at tempered 900oC for 30 minutes in a special fixture sealed with a 10 Ton pressure. Alloy segregation along with delocalized zone of interest is achieved. This process provides high performance and high thickness of coatings.