Mobility of the electron

In Physical, the mobility of a electron connects its speed to the Electric field, in a solid or a gas. One also applies it to the holes and the Ion S in a Gaz.

$v_d = \ driven E$ ,

μ is mobility. When one subjects a material to an electric field, the electrons are accelerated by this field. But they are subjected to the interactions with the atoms of materials and lose their speed at the time of shocks with the atoms. The model of Drude is a simple model (traditional approach) making it possible to model the speed of these electrons and to give an expression of this mobility. One can show, in this approach, that the mobility of a particle is worth:

\ driven = Q \ tau/m*

where Q is the elementary charge,

\ tau

average time between two collisions and m* is the effective mass of the particle. In a semiconductor, the mobility of the electrons is higher than the mobility of the holes.

One generally gives it in cm ²/(V · S). It strongly varies with the impurities (variation of the collision) and with the temperature, and it is difficult to give tables for common materials of them. It is different for the electron S and for the holes in the Semi-conducteur S. When a carrier is dominating the electric Conductivité is proportional to its mobility.

In the Gallium arsenide, with the room temperature, mobility is worth about 2000 cm ²/(V·S).

Mobility can be written as the sum of the influence of the network (of the Phonon S) and that of the impurities:

$\ driven = \ frac {1} {\ frac {1} {\ mu_ {LMBO}} + \ frac {1} {\ mu_ {imp}}}$

It is the rule of Matthiessen.

Random links: