Question

Why hole mobility increases and electron mobility decreases while lod present?

Answer 1

Explanation:

Conduction electrons (free-electrons) travel in the conduction band and valence electrons (holes) travel in the valence band. In an applied electric field, valence electrons cannot move as freely as the free electrons because their movement is restricted. The mobility of a particle in a semiconductor is larger if its effective mass is smaller and the time between scattering events is larger.

Holes are created by the elevation of electrons from innermost shells to higher shells or shells with higher energy levels. Since holes are subjected to the stronger atomic force pulled by the nucleus than the electrons residing in the higher shells or farther shells, holes have a lower mobility.

In an intrinsic silicon, at temperature 300 K:

Electron mobility = 1500 cm2/(V∙s)

Hole mobility = 475 cm2/(V∙s)

Answer 2

Answer:

The mobility of holes and electrons is different because electrons are less bounded in an atom than a hole. Actually hole is basically a vacancy of electron thus they are more bounded to the nucleus of an atom which makes it difficult for them to travel as faster as the electron.