Table of Contents
Mobility is formally defined as the value of the drift velocity per unit of electric field strength; thus, the faster the particle moves at a given electric field strength, the larger the mobility. The mobility of a particular type of particle in a given solid may vary with temperature.
What is the difference between drift velocity and velocity?
The scalar absolute value (magnitude) of velocity is speed, a quantity that is measured in meters per second (m/s or ms1) when using the SI (metric) system. Drift velocity is the average velocity that a particle, such as an electron, attains due to an electric field.
What is meant by the drift velocity and mobility of a free electron?
It is defined as the average velocity with which free electrons get drifted towards the positive end of a conductor (opposite to the electric field) under the influence of an external electric field.
Current flows from higher potential to lower while electrons are attracted towards higher potential and move in the opposite direction of the current. Imagine a piece of conductor and free electrons moving in them.
What is drift mobility?
drift mobility (carrier mobility) (symbol: μ) A quantity that relates the average drift velocity of charge carriers to the electric field strength. Drift mobility is a material parameter, and electrons and holes generally have different mobilities in a given material. …
What is difference between drift and diffusion current?
Diffusion current = the movement caused by variation in the carrier concentration. Drift current = the movement caused by electric fields. Direction of the diffusion current depends on the slope of the carrier concentration. Direction of the drift current is always in the direction of the electric field.
What is SI unit of mobility?
The SI unit of velocity is m/s, and the SI unit of electric field is V/m. Therefore the SI unit of mobility is (m/s)/(V/m) = m2/(V⋅s).
What is tau in drift velocity?
The expression for drift velocity of electrons in a metallic conductor (kept in external electric field) is given by the following relation: In this expression, ‘tau’ represents the average relaxation time of free electrons.