ENGG212: Electronics, Measurements & Transducers - Module I: Electronic Materials

A set of vocabulary flashcards covering the fundamentals of electronic materials, atomic structure, and semiconductor physics from the ENGG212 Module I lecture notes.

Electronics

The science and technology that involves the motion of electrons and ions in vacuum, gas or solid semiconductors.

Atom

The most fundamental unit of matter which consists of three fundamental types of particles: neutrons, protons, and electrons.

Electron

A small, invisible particle of electricity present in all materials which carries a negative charge.

Electron Charge Magnitude

A magnitude of about $1.6 \times 10^{-19}$ Coulombs with negative polarity.

Max Electrons in a Shell Formula

Giving the maximum number of electrons that can be accommodated in a shell, defined as $2n^2$ where $n$ is the shell number.

Duplex Rule

The rule stating that the shell closest to the nucleus can accommodate a maximum of two electrons.

Octet Rule

The observation that atoms generally tend to combine in such a way that each atom has eight valence electrons in its outermost electron shell.

Ground State Energy ($E_0$)

The lowest possible energy state of any atom and the level where all physical systems are in stable equilibrium.

Energy Bands

The closely placed energy levels or range of energies possessed by electrons in different orbits in a solid.

Energy Gap (Forbidden Band)

A region in crystalline solids in which no electron can stay because it is not an allowed energy state, separating the valence and conduction bands.

Valence Band

The energy band containing strongly bounded electrons that cannot gain kinetic energy from an external electric field to contribute to current flo.

Conduction Band

The energy band containing free electrons that require only a small amount of external electric field to contribute to electricity conduction.

Conductors

Metallic materials where the conduction and valence bands overlap, and valence electrons are delocalized and move freely.

Insulators

Materials with a very large forbidden band, typically in the range of $5\,eV$ and more, resulting in high resistivity and very low conductivity.

Semiconductors

Materials with a small forbidden band compared to insulators, where the energy needed for electrons to cross is around $1\,eV$ or less.

Silicon Energy Gap

The magnitude of the energy gap in silicon material, which is $1.1\,eV$.

Germanium Energy Gap

The magnitude of the energy gap in germanium material, which is $0.67\,eV$.

Negative Temperature Coefficient of Resistance

A property of pure semiconductors where electrical resistivity decreases as the temperature increase.

Metallic Bonding

A type of bond in metallic materials where valence electrons are free to move and serve as charge carriers.

Hole

An excess positive charge left in an atom when a valence electron breaks its covalent bond.

Covalent Bonds

Bonds in group four elements where electrons are shared among atoms to achieve complete shells.

Elemental Semiconductors

Semiconductors composed of a single type of element such as germanium (Ge), selenium (Se), and silicon (Si).

Compound Semiconductors

Semiconductors composed of two or more elements, such as Gallium Arsenide ($GaAs$), Gallium Nitride ($GaN$), and Silicon Carbide ($SiC$).

Intrinsic Semiconductors

Pure semiconductor materials where the number of holes is always equal to the number of electrons.

Extrinsic Semiconductors

Substances that have been doped with a doping agent to give them different electrical properties than the original pure material.

Controlled Doping

The careful introduction of impurity atoms into a pure (intrinsic) semiconductor under controlled conditions to increase conductivity.

Donor

A pentavalent doping material that has more valence electrons than the original substrate, used to create n-type semiconductors.

Acceptor

A trivalent doping material that has fewer valence electrons than the original substrate, used to create p-type semiconductors.

N-type Semiconductor

A semiconductor doped with pentavalent impurities where electrons are the majority carriers and holes are the minority carriers.

P-type Semiconductor

A semiconductor doped with trivalent impurities where holes are the majority carriers and electrons are the minority carriers.

Recombination

The process where an electron is recaptured by a broken bond, causing a hole-electron pair to disappear.

Mean Life Time

The average existence of an electron or hole before recombination, usually in the range of $1\,\mu s - 10^3\,\mu s$.

Diffusion Current

A net charge flow resulting from the accumulation of electrons at one end of a semiconductor diffusing to the other end.

Drift Current

Current caused by the movement of free electrons and holes accelerated by an applied electric field.