y the electron does not acquire net acceleration when electric field is applied

Insolid-state physics, theelectron mobilitycharacterizes how quickly anelectroncan move through ametalorsemiconductor, when pulled by anelectric field. In semiconductors, there is an analogous quantity forholes, calledhole mobility. The termcarrier mobilityrefers in general to both electron and hole mobility in semiconductors.

Electron and hole mobility are special cases ofelectrical mobilityof charged particles in a fluid under an applied electric field.

When an electric fieldEis applied across a piece of material, the electrons respond by moving with an average velocity called thedrift velocity,. Then the electron mobility µ is defined as

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