Definitions
Amorphous:
A noncrystalline substance, atoms lack long range order.
Band
gap energy:
Energy difference between the valence and conduction bands.
Conductivity:
The ability to carry an electric current (electricity) or thermal energy (heat).
Covalent
bond:
Bonding by sharing electrons with neighboring elements.
Crystalline:
A solid with a repeating three-dimensional unit cell.
Dielectric
constant:
Relative electrical permittivity of a material as compared to a perfect vacuum.
Glass:
An amorphous solid showing characteristic specific volume behavior over a
certain temperature range.
Imperfection:
Flaw, any deviation from perfection, as in a crystal.
Insulator:
Material that does not conduct electricity (electrical) or heat (thermal).
Ionic
bond:
Electrostatic force between oppositely charged ions.
Laser:
Source of coherent light (Light Amplification by Stimulated Emission of
Radiation).
Piezoelectric:
Material that produces an electrical response to a mechanical force.
Semiconductor:
Nonmetallic material that has a relatively narrow energy band gap.
Superconductivity:
Disappearance of electrical resistivity at low temperatures.
Bias:
voltage applied to the electrodes in an electrical device, considering polarity.
Biasing:
applying a voltage, often done to alter the electrical and optical output of a
device such as a light emitting diode (LED).
Conductor:
a material with a high electrical conductivity such as copper or aluminum.
Crystal:
a solid composed of atoms, ions, or molecules arranged in an orderly pattern
that is repeated in three dimensions.
Diode:
a two electrode semiconductor device that utilizes the rectifying properties of
a p-n junction or a point contact.
Direct Current:
electric current which flows in one direction only.
Dopant:
an impurity element that is deliberately added to a semiconductor.
Electrical
Conductivity:
the ability of a material to carry an electric current; it is the reciprocal of
resistivity with units of ohm [-1] cm[-1].
Electrical
resistance:
the measure of the difficulty of electric current to pass through a given
material; its unit is the ohm ([[Omega]]).
Electron:
a negatively charged sub-atomic particle whose mass is 9.1 x 10[-31]
kg.
Extrinsic
Semiconductor:
a semiconductor material that has been doped with an n-type or p-type element.
Forward Bias:
bias applied to a p-n junction in the conducting direction, majority carrier
electrons and holes flow toward the junction so that a large current flows.
Hole:
a fictitious mobile particle that behaves as though it is a positively charged
particle; holes are produced in the valence band when electrons from the valence
band are promoted to the conduction band or an acceptor level of a p-type dopant.
Insulator:
a material with a low electrical conductivity; a type of material having a lower
energy valence band that is nearly completely filled with electrons and a higher
conduction band that is nearly completely empty of electrons as a result of a
large energy gap between the two bands.
Integrated
Circuit (IC):
a single semiconductor chip or wafer which now contains thousands or millions of
circuit elements per square centimeter.
Intrinsic
Semiconductors:
a semiconductor material that is essentially pure.
Light Emitting
Diode (LED)
: a semiconductor p-n junction device that is optimized to release light of
approximately the band gap energy when electrons fall from the conduction band
to the valence band.
N-Type
Semiconductor:
a semiconductor that has been doped with an electron donor.
P-N Junction:
a boundary between p-type and n-type regions within a single crystal of a
semiconductor material, a diode.
P-Type
Semiconductor:
a semiconductor that has been doped with an electron acceptor.
Resistor:
a device used in electric circuits to limit the current flow or to provide a
voltage drop.
Reverse Bias:
bias applied to a p-n junction in a direction for which the flow of current is
inhibited; majority carrier electrons and holes flow away from the junction.
Semiconductor:
a material whose electrical conductivity is midway between that of an good
conductor and a good insulator; a type of material having a lower energy valence
band that is nearly completely filled with electrons and a higher energy
conduction band that is nearly completely empty of electrons, with a modest
energy gap between the two bands; pure materials usually exhibit electrical
conductivity that increases with temperature because of an increase in the
number of charge carriers being promoted to the conduction band.
Transistor: a solid state semiconductor device able to amplify a signal in forward bias.
Switch:
Amplifier:
Floppy Disk:
Ferro-magnetic:
Magnetic Field:
Magnetization:
Cathode Ray Tube (CRT):
Pixel:
Polarizing:
Substrates: