ENGG212 - Electronics, Measurements and Transducers: Electronic Materials

Vocabulary practice flashcards covering fundamental electronic materials, atomic structure, energy band theory, and semiconductor physics from the ENGG212 module.

Electronics

The science and technology that involves the motion of electrons and ions in vacuum gas or solid semiconductors, as well as the study of information and energy processing.

Information processing

The use of electronic devices such as computers, routers, switches, and multiplexers for communication purposes.

Energy processing

The conversion of electrical energy into another form of energy such as light, heat, or sound.

Electron

A small, invisible particle of electricity present in the atoms of all matter, carrying a negative charge of magnitude approximately $1.6 \times 10^{-19}$ coulombs.

Nucleus

The center of an atom formulated by neutrons and protons, where the total mass of the atom is concentrated.

Duplex Rule

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

Octet Rule

A rule stating that an orbit other than the one nearest to the nucleus can contain a maximum of eight electrons for any atom in a stable state.

Ground state energy

The lowest possible energy state of any atom, denoted as $E_0$.

Energy bands

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

Energy gap (forbidden band)

The region between the valence and conduction bands in which no electron can stay because there is no allowed energy state.

Valence Band

The energy band containing strongly bounded electrons located below the forbidden band.

Conduction Band

The energy band containing free electrons which need only small amounts of an external electric field to contribute to electricity conduction.

Conductors

Materials, typically metals, where the forbidden band does not exist and the conduction and valence bands overlap ($E_G = 0\,eV$).

Insulators

Materials where the valence band is completely filled and the conduction band is empty, with a very large energy gap ($E_G \geq 5\,eV$).

Semiconductors

Materials that conduct electricity more than insulators but less than pure conductors, having a small energy gap of around $1\,eV$ or less.

Silicon energy gap

The energy needed for electrons to jump from the valence band to the conduction band in silicon, which is $1.1\,eV$.

Germanium energy gap

The energy needed for electrons to jump from the valence band to the conduction band in germanium, which is $0.67\,eV$.

Negative temperature coefficient of resistance

A property of semiconductor materials where electrical resistivity decreases as temperature increases.

Hole

An excess positive charge left in an atom when a valence electron breaks its bond and moves to the conduction band.

Elemental semiconductors

Semiconductors made of a single element from the periodic table, such as germanium (Ge), selenium (Se), and silicon (Si).

Compound semiconductor

A semiconductor substrate consisting of chemical compounds of two or more elements, such as Gallium Arsenide (GaAs), Gallium Nitride (GaN), or Silicon Carbide (SiC).

Intrinsic semiconductors

Pure semiconductors where no impurity has been introduced and the number of holes is equal to the number of electrons.

Extrinsic semiconductors

Impure semiconductors formed by adding a doping agent to a pure semiconductor to change its electrical properties.

Doping

The process of carefully introducing impurity atoms into a pure (intrinsic) semiconductor under controlled conditions to increase conductivity.

Donor

A pentavalent (Group 5) impurity element, such as phosphorus or arsenic, that provides excess electrons to the semiconductor structure.

Acceptor

A trivalent (Group 3) impurity element, such as boron or aluminum, that creates excess holes in the semiconductor structure.

N-type (negative) semiconductor

An extrinsic semiconductor doped with pentavalent donor impurities where electrons are the majority carriers and holes are the minority carriers.

P-type (positive) semiconductor

An extrinsic semiconductor doped with trivalent acceptor impurities where holes are the majority carriers and electrons are the minority carriers.

Recombination

The process occurring when an electron moves close to a hole and is recaptured by a broken bond, releasing energy as heat or light.

Mean life time

The average time of existence of an electron or hole before recombination, usually ranging from $1\, \mu s$ to $10\, \mu s$.

Diffusion current

A net charge flow resulting from carriers moving from a region of higher concentration to a region of lower concentration.

Drift velocity

The average uniform velocity that a particle (electron) attains in a material due to the application of an electric field.

Mobility

A measure of how quickly an electron or hole moves through a semiconductor in the presence of an electric field, measured in $m^2/Vs$.

Conductivity formula ($\sigma$)

The expression for the ability of a material to conduct electricity, given by $\sigma = nq\mu$.

Volt-equivalent of temperature ($V_T$)

A thermal voltage value defined as $V_T = \frac{KT}{q}$, where $K$ is the Boltzmann constant, $T$ is temperature in Kelvin, and $q$ is the charge of an electron.