18 Questions
What type of crystal defect involves a host ion being displaced into an interstitial position?
Frenkel defect
Which crystal defect results in a missing cation-anion pair that may migrate to the surface?
Schottky defect
How do line defects in a crystal form?
By displacement of one plane to the other
What crystal defect involves an impurity atom substituting directly for the host atom?
Substitutional impurity
Which crystal defect contributes significantly to the resistivity of materials and causes leakage current in PN junctions?
Edge dislocation
How do vacancies in crystals impact the diffusion of impurities?
They increase impurity diffusion
What is the main characteristic of crystalline solids?
Periodic array of points in space
How many confirmed elements are there in the current standard table as of 2021?
118
What are the applications of solid polonium mentioned in the text?
Heaters in space probes
Which element is extremely dangerous to humans as mentioned in the text?
Polonium
What is the primary application of Po-based sources mentioned in the text?
Measuring the thickness of industrial coatings via alpha radiation attenuation
In what allotropes does Polonium exist as a radioactive element?
Alpha and Beta
Which type of crystal defect is characterized by a break in the regular arrangement of atoms?
Line defects
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?
Epitaxial growth
Which lattice structure has atoms located at the corners of a cube and one at the center of the cube?
Body Centered Cubic
According to the Drude model, what does drift velocity refer to?
Velocity of electrons under acceleration
What property does the Hall effect measure in a material?
Mobility of charge carriers
Which type of lattice defect involves a missing atom or a foreign atom replacing a host atom within the crystal structure?
Point defects
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.
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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