Electrical Conductivity in Intrinsic Semiconductors

At absolute zero (0 Kelvin), the Fermi level is positioned exactly halfway between the conduction band and the valence band in an intrinsic semiconductor.

When temperature is above absolute zero (T > 0 K), the Fermi level shifts slightly upwards due to the higher mobility of holes compared to electrons.

The electrical conductivity of a pure semiconductor is determined by the exponential relationship between the band gap energy, the mobility of electrons and holes, and the temperature.

The band gap energy of an intrinsic semiconductor can be determined by measuring the resistance at different temperatures and plotting a graph of log(resistance) vs 1/temperature.

A semiconductor in which impurity atoms have been intentionally added (doped) to increase its conductivity.

Impurity atoms with more valence electrons than the semiconductor material (e.g., phosphorus in silicon) donate extra electrons to the material, creating 'n-type' semiconductor.

A semiconductor where the addition of donor impurities increases the concentration of free electrons, making it more conductive.

Impurity atoms with fewer valence electrons than the semiconductor material (e.g., boron in silicon) create 'holes' in the valence band, creating 'p-type' semiconductor.

A distinct energy level close to the conduction band in an N-type semiconductor, where the free electrons donated by donor impurities reside before being excited to the conduction band.

A distinct energy level close to the valence band in a P-type semiconductor, where the electrons accepted by acceptor impurities reside.

The principle that the total positive charge density (from holes) must equal the total negative charge density (from free electrons) in both intrinsic and extrinsic semiconductors.

In an N-type semiconductor, the free electron concentration (Ne) is equal to the density of donor atoms (ND), because the number of free electrons released by the donor atoms is larger than the number of holes.

The energy level within the band gap of a P-type semiconductor that represents the energy required to remove an electron from the valence band and create a hole.

At absolute zero (0K), the Fermi level in a P-type semiconductor lies exactly in the middle of the acceptor level (EA) and the top of the valence band (EV).

The energy level within the band gap of an N-type semiconductor that represents the energy required to excite an electron from the donor level to the conduction band.

At absolute zero (0K), the Fermi level in an N-type semiconductor lies exactly in the middle of the conduction band (EC) and the donor level (ED).

The energy required to remove an electron from a bound state (like the valence band or donor level) to a free state (like the conduction band or acceptor level).

When a semiconductor material behaves like an intrinsic semiconductor, meaning its conductivity is primarily due to electron-hole pairs created by thermal energy.

The Fermi Level (EF) represents the energy level at which there's a 50% probability of finding an electron at a given temperature. It's a crucial concept in understanding how semiconductors work and how they conduct electricity.

In a p-type semiconductor, as temperature increases, some electrons from the valence band move up to the acceptor energy level (EA). This causes the Fermi Level to shift upward. At very high temperatures, it reaches the intrinsic level (Ei).

Increasing the concentration of acceptor impurities (like boron in silicon) in a p-type semiconductor leads to an increase in hole concentration. This causes the Fermi Level to shift downward.

The intrinsic carrier concentration (ni) represents the concentration of free electrons and holes in a pure semiconductor at a given temperature. It's a fundamental property of semiconductors used to calculate their conductivity.

Conductivity is a measure of how well a material can conduct electricity. In semiconductors, it depends on the concentration of free charge carriers (electrons and holes) and their mobility (how easily they move).

Conductivity of a semiconductor is influenced by: 1) Concentration of charge carriers: More carriers = higher conductivity. 2) Carrier mobility: How easily electrons and holes move. 3) Temperature: Higher temperature typically increases conductivity.

Resistivity is the opposite of conductivity. It measures a material's resistance to the flow of electricity. Higher resistivity means harder to conduct electricity.

For an intrinsic semiconductor with a band gap of 0.7 eV, the Fermi Level (EF) is located at the midpoint of the bandgap when T = 300K, assuming the effective mass of holes (mh) is 6 times that of electrons (me).