Sunday, 16 April 2017

Difference between hole and electron

           Electron and hole are the two charge carriers that are present in a semiconductor material. The electron is the majority carrier in an N-type semiconductor and hole is the majority carrier in P-type Semiconductor. The N-type and P-type semiconductors are called as extrinsic semiconductors as these are doped with the external impurities i.e., P-type has trivalent impurities while N-type has penta-valent impurities. The intrinsic semiconductor (pure form of semiconductor) is doped with impurities to form P type and N type semiconductors. The intrinsic semiconductor is said to behave as an Insulator at absolute zero (0 deg c). The electron and hole have same mass and charge but electron has negative charge while hole has positive charge.

  • Electron is negatively charged and its value is given as 1.6022 x 10-19 Coulomb.
  • Hole is positively charged and its value is given as 1.6022 x 10-19 Coulomb.
  • Mass of electron and hole:  9.1 x 10-31 kg.


         A hole is said to be absence of electron in the valence band, then how will a physically non existing element have mass and charge. This can be understood as follows. Consider the diagram below in the valence band of a P-Type semiconductor.


             Assume semiconductor at room temperature there will be continuous breakdown and creation of covalent bonds in the valence band which is generation and recombination of electrons and holes consider a bond breakage takes place and electron will move from one location and occupy another vacant location in the valence band as follows. In the series of diagrams the location of electron moving from right to left can be seen which resembles as if a hole is moving from left to right.


               From the above series of diagrams an electron movement in the valence band is considered as hole movement in opposite direction and thus a physically non existing material has mass and charge. In semiconductor materials hole is always considered on valence band and electron is always considered in conduction band.

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