Semiconductor Physics Quiz

A collection of closely packed energy levels in a solid.

The lower energy band in a solid, containing valence electrons.

The higher energy band in a solid, usually empty or partially filled at room temperature.

The energy gap between the valence band and conduction band in a solid.

A material with low resistivity and high conductivity, allowing easy flow of electricity.

A material with high resistivity and low conductivity, resisting the flow of electricity.

A material that behaves like an insulator at low temperatures but conducts electricity at higher temperatures.

A semiconductor made from a pure element, without any impurities added.

Materials that exhibit conductivity between that of a conductor and an insulator, with their conductivity highly dependent on temperature and impurities.

The ability of a material to conduct electricity. Semiconductors are unique because their conductivity can be changed by adding impurities.

The state of a semiconductor at 0 Kelvin (absolute zero), where it acts as an insulator, meaning it does not conduct electricity.

The movement of electrons and holes within a semiconductor material, contributing to its conductivity.

Positively charged particles within a semiconductor, formed when an electron leaves its bond, leaving behind a 'hole'.

Adding impurity atoms to an intrinsic semiconductor to increase its conductivity.

Impurity atoms with five valence electrons, such as phosphorus or arsenic.

Impurity atoms with three valence electrons, such as boron or aluminum.

The average velocity of free electrons in a semiconductor due to thermal energy is zero. This is because the electrons move randomly in all directions.

The force exerted on an electron in a semiconductor by an electric field is directly proportional to the strength of the field and the charge of the electron. This force causes the electron to accelerate in the direction opposite to the field.

The acceleration of an electron in a semiconductor due to an electric field is determined by the force acting on it and its mass. The acceleration is in the direction opposite to the field.

The drift velocity is the average velocity achieved by free electrons in a semiconductor due to the influence of an electric field. It is directly proportional to the electric field strength, the time between collisions (relaxation time), and the charge-to-mass ratio of the electron.

The conductivity of a semiconductor is a measure of how easily it conducts electricity. It is directly proportional to the number of free electrons, the charge of an electron, the relaxation time, and the drift velocity.

The mobility of a semiconductor is a measure of how easily electrons or holes move under the influence of an electric field. It is directly proportional to the charge-to-mass ratio and the relaxation time.

The current density in a semiconductor is directly proportional to the drift velocity of the free electrons. A higher drift velocity results in a larger current.

The average time between collisions between free electrons in a semiconductor is known as the relaxation time. It is a key factor in determining the conductivity and mobility of a semiconductor.

The volume of a conductor is given by the product of its cross-sectional area (A) and length (l).

Current in a conductor is the product of the charge of an electron (e), the number density of free electrons (n), the drift velocity of electrons (v_d), and the cross-sectional area (A) of the conductor.

The current density due to the drift velocity of free electrons is given by J_e = -ne(v_d), where e is the charge of an electron, n is the free electron density, and v_d is the drift velocity.

The current density due to the drift velocity of holes is given by J_h = eh(v_d), where h is the hole density, and v_d is the drift velocity.

The total current density in a semiconductor is the sum of the current densities due to both free electrons and holes.

Mobility ("mu") is the ratio of drift velocity (v_d) to the electric field (E). It's basically how responsive the charge carriers are to an electric field.

The mobility of electrons ("mu_e") is negative because electrons move in the opposite direction of the electric field, while the mobility of holes ("mu_h") is positive. They have the same magnitude but opposite signs.

A semiconductor material that is doped with impurities that have more valence electrons than the intrinsic semiconductor. Example: Germanium (Ge) doped with Arsenic (As).

In an n-type semiconductor, the majority charge carriers are free electrons, created by the donor impurities.

In an n-type semiconductor, the minority charge carriers are holes, which are the absence of an electron in the valence band.

A semiconductor material that is doped with impurities that have fewer valence electrons than the intrinsic semiconductor. Example: Germanium (Ge) doped with Indium (In).

In a p-type semiconductor, the majority charge carriers are holes, created by the acceptor impurities.

In a p-type semiconductor, the minority charge carriers are free electrons.

The average velocity of charge carriers (electrons and holes) in a semiconductor when an electric field is applied.

The density of minority charge carriers in a semiconductor is equal to the density of impurity atoms.