In absence of an electrical field, the free electrons (electron gas) move in all directions in a random manner.
CARRIER TRANSPORT IN SEMICONDUCTOR MOBILITY In absence of an electrical field, the free electrons (electron gas) move in all directions in a random manner. They collide with other free electrons and positive ion core during the motion. This collision is known as elastic collision (Fig 3.12). Fig. 3.12 Random motion of free electrons in the absence of electric field (+ ve ion cores are not shown). As the motion is random, the resultant velocity in any particular direction is zero. When an electrical field is applied in a semiconducting material, the free charge carriers such as free electrons and holes attain drift velocity vd. The drift velocity attained by the carriers is proportional to the electrical field strength E. where μ is a proportionality constant and it is known as the mobility of the charge carrier. This velocity vd is different for different semiconductors and for different types of charge carriers.
Materials Science: Unit III: Semiconductors and Transport Physics : Tag: : - Carrier Transport in Semiconductor Mobility
Materials Science
PH3251 2nd semester Mechanical Dept | 2021 Regulation | 2nd Semester Mechanical Dept 2021 Regulation