Semiconductor Devices and Energy Band Gap Theory

A theory explaining the quantum states of electrons in solid metals. It describes how electrons behave in molecules, showing how atomic orbitals combine to form molecular orbitals with distinct energy levels. In solids, these levels form energy bands.

The highest occupied energy band in a solid, containing valence electrons, the outermost electrons in an atom.

The lowest unoccupied energy band in a solid. It contains conduction electrons, which are free to move and carry current. Electrons in this band are loosely bound.

The energy gap between the valence band and the conduction band in a solid. No electrons can occupy this region.

Materials with overlapping valence and conduction bands, allowing valence electrons to easily move, enabling electrical conductivity.

Materials with a large forbidden gap between the valence and conduction bands, making it difficult for electrons to move and hindering electrical conductivity.

Materials with a moderate forbidden gap between valence and conduction bands, enabling electrical conductivity under certain conditions like temperature.

A range of closely spaced energy levels in a solid. These energy levels arise from the interaction of many atoms.

A p-n junction is a boundary between a p-type and an n-type semiconductor region. This boundary acts as a diode, a component that allows current to flow only in one direction.

A region near the p-n junction with no free charge carriers, formed by electron-hole recombination.

Applying an external voltage across the p-n junction that allows current to flow.

Applying an external voltage across the p-n junction so that it blocks current flow.

Electrons are the majority charge carriers in the n-type semiconductor.

Holes are the majority charge carriers in the p-type semiconductor.

The concentration of dopants (impurities) in a semiconductor material, affecting the width of the depletion region.

The methods used to create a p-n junction include grown junction, alloying, and diffusion.

A region within a PN junction where there are very few free charge carriers (electrons or holes). It forms due to the diffusion of charge carriers across the junction.

The reverse voltage at which the current through a reverse-biased diode increases sharply. This is caused by excessive energy gained by minority carriers.

A specially designed diode that allows a controlled breakdown in the reverse direction. It has a specific breakdown voltage (Vz) which can be used for voltage regulation.

The relationship between the voltage applied across a diode and the current flowing through it. This is represented by a graph showing current (I) on the y-axis and voltage (V) on the x-axis.

A device that converts alternating current (AC) to direct current (DC). Diodes are often used as rectifiers.

A diode that emits light when forward biased. The color of light depends on the semiconductor material used.

A type of rectifier circuit that converts alternating current (AC) to direct current (DC) by utilizing both half-cycles of the input AC waveform.

A rectifier circuit that utilizes four diodes arranged in a bridge configuration to enable current flow during both positive and negative half-cycles of the input AC signal.

The frequency of the output DC waveform produced by a full wave rectifier is double the frequency of the input AC signal.

A three-terminal semiconductor device that allows current to flow from a high resistance region to a low resistance region, acting as both a switch and an amplifier.

A type of transistor with three terminals: base, emitter, and collector, constructed from layers of semiconductor materials.

The control terminal in a transistor. A small current applied to the base can significantly control the flow of a larger current between the collector and emitter terminals.

The terminal of a transistor that emits a stream of electrons or holes.

The terminal of a transistor that collects the majority of the current flowing from the emitter to the collector.

A semiconductor material where the number of free electrons (n) and holes (p) are equal to the intrinsic carrier concentration (ni) at a given temperature.

The voltage drop across a diode when it's conducting current in the forward direction.

A circuit that maintains a constant output voltage even if the input voltage or load current varies.

The amount of current flowing through the external load connected to a circuit.

A type of transistor that amplifies signals by controlling a larger current with a smaller one.

A type of BJT with two p-type regions separated by an n-type region. The current flows from the emitter to the collector.

A type of BJT with two n-type regions separated by a p-type region. The current flows from the emitter to the collector.

A transistor configuration where the base is common between the input and output terminals.

A transistor configuration where the collector is common between the input and output terminals.

A transistor configuration where the emitter is common between the input and output terminals.

The number of free electrons and holes in an intrinsic semiconductor. It is determined by the material's properties and temperature.

To convert a value from cm⁻³ to m⁻³, multiply by 10⁶.