ELECTRONICS
It is the branch of physics that deals with the emission and effects of electrons and the operation of
electronic devices.
Semiconductors                                                  The majority carriers move against the
                                                                 direction of conventional current.
It is a substance, usually a solid chemical
element or compound, that can conduct                       p-type Semi-Conductor
electricity under some conditions but not
others, making it a good medium for the                         It is an extrinsic semi-conductor which is
control of electrical current.                                   obtained by doping the impurity atoms of
                                                                 III group of the periodic table to the pure
A pure semiconductor is called intrinsic                         Ge and Si semi-conductor.
semiconductor. It has equal numbers of                          The impurity atoms added, create vaccines
negative carriers (electrons) and positive                       of electrons (i.e. holes) in the structure and
carriers (holes).                                                are called acceptor atoms.
                                                                The majority carriers are holes which
An impure semiconductor is called extrinsic
                                                                 move in the valence band.
semiconductor. There are two types of
                                                                The majority carriers move in the direction
extrinsic semiconductor.
                                                                 of conventional current
1. n-type
                                                            p-n Junction
2. p-type
                                                            It is an arrangement consisting a p-type
n-type Semi-Conductor
                                                            semiconductor brought into a close contact
    It is an extrinsic semi-conductor which is             with n-type semiconductor.
     obtained by doping the impurity atoms of
                                                            The Noble prize in physics 2014 was awarded
     Vth group of the periodic table to the pure
                                                            jointly to Isamu Akasaki, Hiroshi Amano and
     Ge and Si semi-conductor.
                                                            Shiji Nakamura, for inventing a new energy
    The impurity atoms added, provide extra
                                                            efficient and environment friendly light
     electrons in the structure and are called
                                                            sourcethe blue Light Emitting Diode (LED).
     donor atoms.
    The majority carriers are electrons that
     move in the conduction band.
                          PN diode (a) functional diagram, and (b) schematic diagram
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