Solid State Physics and Electronic Materials Laboratory

Punit Boolchand

The following research is being conducted in the lab:

  • Self-Organization in Disordered Networks - Discovery of Intermediate Phases in network or molecular glasses has opened a novel paradigm to understand the physical behavior of glasses at a basic level. These phases manifest as global connectivity of molecular networks are systematically changed, and acquire a critical value. These ideas have led to a glass structure based classification in terms of their elastic properties.
  • Solid Electrolytes - Ag as an additive in Chalcogenide glasses has attracted widespread interest in optical recording and information storage technologies. Ag as a chemical additive plays a dual role; in Se-rich glasses it macroscopically phase separates into a Ag-rich glass phase, and in Se deficient glasses becomes a network former to replace Ge in select local environments. The Ag-rich glass phase is thought to be a solid electrolyte with a stoichiometry close to Ag2Se, and is characterized by a glass transition of 230°C. An equally important consequence of Ag addition to oxide and chalcogenide base glasses is the several orders of magnitude enhancement of electrical conductivity of the alloyed glasses.
  • Rare-Earth Additives In Chalcogenide Glasses and Crystalline Oxides - Rare-earth as additives in Chalcogenide glasses have attracted widespread interest as optical amplifiers, lasers, mid-IR photonic materials because of the high refractive index and mid IR transparency1. Most rare-earth ions in  solids stabilize in the trivalent state, although exceptions  can occur for Eu (divalent) and Ce(tetravalent). For these reasons trivalent  Ga as an additive in the chalcogenide glasses has been extensively studied2,3. Although Rare-earth ions can replace Ga sites in such glasses, this does not necessarily have to be the case. In some cases, Rare-earth ions can also occupy distorted rocksalt environment, as is found for the case of  Rare-earth monosulfides such as LaS.
  • Negative Electron Affinities, New Cold Cathode and Organic Light Emitting Diodes - Rare-earth monosulphides, such as LaS and NdS, are unusual metals as they possess low work-functions. These materials in conjunction with  III-V or II-VI semiconductors  and separately with light emitting polymers, can be used as efficient cold cathode emitters and light emitting devices. An effort to synthesize bulk materials of the rare-earth sulfides, and grow thin-films of the rare-earth sulfides by sputtering and evaporation is made, to fabricate new solid state cold cathode emitters and efficient and durable organic light emitting diodes ( OLEDS).
    Current research efforts are directed towards growth of thin-films of various rare-earth sulfides on compound semiconductors by RF  magnetron sputtering deposition.
  • Synthesis and Nanostructure of Super Hard Thin-Films - Films in the B-N-C ternary are of interest because of their super hardness.  The ternary encompasses some of the hardest crystalline materials known including diamond, BN, B2C. A collaborative effort to synthesize and characterize nanostructure of vapor deposited thin-films is ongoing with Professor Raj Singh (Materials Science and Engineering, University of Cincinnati) and  with Professor Hans-Joachim Kleebe (Colorado School of Mines). At the core of the research effort is an ECR microwave plasma enhanced CVD facility (Professor R.Singh)  for growth of the ternary alloy films. The films are characterized by x-ray diffraction, and Raman scattering  (Professor P.Boolchand) and Electron microscopy including HRTEM, SEM and EELS (Professor H.-J.Kleebe). The mechanical properties of these films including Hardness, Elastic Moduli, and thermal conductivity (Professor Singh) are measured. Constraint counting algorithms&

  • SmartLab® High-resolution 3 kW X-ray Diffractometer

    SmartLab® high-resolution 3 kW X-ray diffractometer for Powder diffraction, thin film diffraction, and in-plane scattering.

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  • T 64000 Jobin Yvon Triple Monochromator System

    T 64000 Jobin Yvon Triple Monochromator System

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  • EG & G PAR Model 4500, Vibrating Sample Magnetometer System

    EG & G PAR Model 4500, Vibrating Sample Magnetometer System

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  • Liquid Helium Cryostat

    Liquid Helium Cryostat

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  • Perkin-Elmer DSC Model 2C Instrument

    Perkin-Elmer DSC model 2C instrument

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  • Perkin Elmer TGA7 unit

    Perkin Elmer TGA7 unit to characterize oxygen weight loss in cuprate semiconductors.

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  • Perkin Elmer DMA7 unit

    Characterize alpha- and beta- relaxation in network glasses..

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  • Cooke Vacuum System Model CVE-600MC

    The system has been used to deposit high-Tc thin films of YBCO both on-axis and off-axis. The system is now being adapted to deposit CdS and LaS films.

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