Electrons and Holes

Hole:

An empty state in the valence band is reffered to as hole.

Electron Hole Pair(EHP):

If the conduction band electron and the hole are created by the excitation of a valence band electron to the conduction band, they are called an electron-hole pair.

Comments

Naturally an individual atom has orbitals of different energy levels which can be represented by wave functions. When the atoms are brought together, their antibonding atoms diminisles and bonding orbitals form a band of energy.

Qualitative Band Diagram of Intrinsic and Extrinsic Materials

Probablity Distribution Function

Electrons are fermions, which satisfy the exclusion principle. So, it maintains the Fermi-Dirac distribution. Where, K is Boltzmann’s constant. K=1.38×10 -23 J/K Or K=8.62×10 -5 eV/K T is absolute temperature. E F is Fermi level. Let, E=E F So that, f(E)= ½ So E F is the Fermi energy level at which the PDF is ½ . If T=0K the distribution takes the simple rectangular, shown in figure.

Solid State Devices

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