Types of Crystal Defects: Point Defects Overview
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Questions and Answers

What type of crystal defect involves a host ion being displaced into an interstitial position?

  • Screw dislocation
  • Frenkel defect (correct)
  • Edge dislocation
  • Schottky defect
  • Which crystal defect results in a missing cation-anion pair that may migrate to the surface?

  • Interstitial impurity
  • Edge dislocation
  • Schottky defect (correct)
  • Substitutional impurity
  • How do line defects in a crystal form?

  • By displacement of one plane to the other (correct)
  • By hosting impurity atoms in interstitial positions
  • By a shearing of one portion of the crystal with respect to another
  • Due to lattice changes or distortions of atomic distances
  • What crystal defect involves an impurity atom substituting directly for the host atom?

    <p>Substitutional impurity</p> Signup and view all the answers

    Which crystal defect contributes significantly to the resistivity of materials and causes leakage current in PN junctions?

    <p>Edge dislocation</p> Signup and view all the answers

    How do vacancies in crystals impact the diffusion of impurities?

    <p>They increase impurity diffusion</p> Signup and view all the answers

    What is the main characteristic of crystalline solids?

    <p>Periodic array of points in space</p> Signup and view all the answers

    How many confirmed elements are there in the current standard table as of 2021?

    <p>118</p> Signup and view all the answers

    What are the applications of solid polonium mentioned in the text?

    <p>Heaters in space probes</p> Signup and view all the answers

    Which element is extremely dangerous to humans as mentioned in the text?

    <p>Polonium</p> Signup and view all the answers

    What is the primary application of Po-based sources mentioned in the text?

    <p>Measuring the thickness of industrial coatings via alpha radiation attenuation</p> Signup and view all the answers

    In what allotropes does Polonium exist as a radioactive element?

    <p>Alpha and Beta</p> Signup and view all the answers

    Which type of crystal defect is characterized by a break in the regular arrangement of atoms?

    <p>Line defects</p> Signup and view all the answers

    In crystal growth, which process involves the deposition of one crystal on another, where the orientation of the deposited crystal follows that of the substrate crystal?

    <p>Epitaxial growth</p> Signup and view all the answers

    Which lattice structure has atoms located at the corners of a cube and one at the center of the cube?

    <p>Body Centered Cubic</p> Signup and view all the answers

    According to the Drude model, what does drift velocity refer to?

    <p>Velocity of electrons under acceleration</p> Signup and view all the answers

    What property does the Hall effect measure in a material?

    <p>Mobility of charge carriers</p> Signup and view all the answers

    Which type of lattice defect involves a missing atom or a foreign atom replacing a host atom within the crystal structure?

    <p>Point defects</p> Signup and view all the answers

    Study Notes

    Crystal Defects

    • An interstitial defect occurs when a host ion is displaced into an interstitial position.
    • A Schottky defect results in a missing cation-anion pair that may migrate to the surface.
    • Line defects, also known as dislocations, form when a row of atoms in a crystal is disrupted.

    Substitutional Defects

    • A substitutional impurity occurs when an impurity atom substitutes directly for a host atom.

    Electrical Properties

    • Impurities can significantly contribute to the resistivity of materials and cause leakage current in PN junctions.

    Diffusion of Impurities

    • Vacancies in crystals impact the diffusion of impurities by providing sites for impurities to occupy.

    Crystalline Solids

    • The main characteristic of crystalline solids is that their atoms are arranged in a repeating pattern.

    Elements

    • As of 2021, there are 118 confirmed elements in the standard table.

    Polonium

    • Solid polonium has applications in the production of radioisotope thermoelectric generators and atomic batteries.
    • Polonium is extremely dangerous to humans due to its high radioactivity.
    • The primary application of Po-based sources is in the production of radioisotope thermoelectric generators.
    • Polonium exists as a radioactive element in two allotropes: α-polonium and β-polonium.

    Crystal Growth

    • Epitaxy is a process in a crystal growth where the deposition of one crystal on another occurs, and the orientation of the deposited crystal follows that of the substrate crystal.

    Lattice Structures

    • A body-centered cubic lattice structure has atoms located at the corners of a cube and one at the center of the cube.

    Drude Model

    • Drift velocity refers to the average velocity of charge carriers in a material under an electric field.

    Hall Effect

    • The Hall effect measures the transverse voltage developed across a material when an electric current flows through it in the presence of a magnetic field.

    Lattice Defects

    • A point defect involves a missing atom or a foreign atom replacing a host atom within the crystal structure.

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    Description

    Explore the various types of point defects in crystals, including vacancies, substitutions, interstitial impurities, Schottky defects, and Frenkel defects. Understand how these defects occur and their impact on crystal structures.

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