Semiconductor Physics

1. When items are held together by the sharing of valence electron

•  they form a covalent bond

• each atom becomes free to move 

• each shared electron leaves a hole

•  the valence electrons are free to move away from the atom

An electron in the conduction band

•  is bound to its parent atom

•  is located near the top of the Crystal

• has no charge

•  has higher energy than an electron in the valence band

1.   And intrinsic semiconductor and absolute zero of temperature

•  behaves like an insulator

   

• has a few holes and same number of electrons

• has a large number of holes

   

•  behaves like a metallic conductor

1.  Donor type impurities

•  create excess holes

•  can be added to Germanium but not to Silicon

•  must have five valance electrons

•  must have three valence electrons

1. The conduction band

•  is not an allowed energy band

•  is a range of energy corresponding to the energy  of free electrons

•  is always called the  Forbidden energy gap

•  is always located at the top of the Crystal

1.  the  The Forbidden energy gap in semiconductors

•  is the same As the Valence band

• lies between the valence band and the conduction band

•  lies just about the conduction band

•  lies just below the valence band

   

1.  in an entire semiconductor the concentration of minority careers mainly depends on

•  the quality of the intrinsic material

•  the temperature of the material

•  the number of Donor atoms

•  the doping technique

1. The electrons in the outermost orbit are called ___________ electrons

1. The larger the orbit the ______ is the energy of the electrons

1.  the merging of a free electron and a hole is called _______