, Semiconductors ( Ref https://www.youtube.com/watch?v=H6Lh4XoIbGw)
Semiconductors are materials which have a conductivity between conductors and insulators .
Semiconductors can be compounds, such as gallium arsenide, or pure elements, such as germanium or
silicon.
Holes and Electrons in Semiconductors
Holes and electrons are the types of charge carriers accountable for the flow of current in
semiconductors. Holes (valence electrons) are the positively charged electric charge carrier,
whereas electrons are the negatively charged particles. Both electrons and holes are equal in magnitude
but opposite in polarity. mobility of electrons is higher than that of the holes
Valence Band: The energy band involving the energy levels of valence electrons is known as the valence
band
Conduction Band: It has conducting electrons resulting in the flow of current. The conduction band in
semiconductors accepts the electrons from the valence band.
The band gap is the energy difference between the valence band and the conduction band. In
semiconductors, this gap is small enough that electrons can gain enough energy to jump from the valence
band to the conduction band.
The size of the band gap determines the semiconductor's properties:
• Small Band Gap: Easier for electrons to move to the conduction band, leading to higher
conductivity.
• Large Band Gap: Harder for electrons to jump to the conduction band, leading to lower
conductivity.
Intrinsic semi conductors (https://www.youtube.com/watch?v=xjL9ayRg1aY&t=1s)
• Intrinsic semiconductors are made of a pure substance, with no added impurities. The most
common materials used as intrinsic semiconductors are silicon (Si) and germanium (Ge).
Intrinsic semiconductors, charge carriers (electrons and holes) are generated by thermal excitation.
When an electron gains enough thermal energy, it can jump from the valence band to the conduction
band, leaving behind a "hole" in the valence band. These holes act as positive charge carriers. When an
electron jumps from the valence band to the conduction band, it creates an electron-hole pair. In an
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Semiconductors are materials which have a conductivity between conductors and insulators .
Semiconductors can be compounds, such as gallium arsenide, or pure elements, such as germanium or
silicon.
Holes and Electrons in Semiconductors
Holes and electrons are the types of charge carriers accountable for the flow of current in
semiconductors. Holes (valence electrons) are the positively charged electric charge carrier,
whereas electrons are the negatively charged particles. Both electrons and holes are equal in magnitude
but opposite in polarity. mobility of electrons is higher than that of the holes
Valence Band: The energy band involving the energy levels of valence electrons is known as the valence
band
Conduction Band: It has conducting electrons resulting in the flow of current. The conduction band in
semiconductors accepts the electrons from the valence band.
The band gap is the energy difference between the valence band and the conduction band. In
semiconductors, this gap is small enough that electrons can gain enough energy to jump from the valence
band to the conduction band.
The size of the band gap determines the semiconductor's properties:
• Small Band Gap: Easier for electrons to move to the conduction band, leading to higher
conductivity.
• Large Band Gap: Harder for electrons to jump to the conduction band, leading to lower
conductivity.
Intrinsic semi conductors (https://www.youtube.com/watch?v=xjL9ayRg1aY&t=1s)
• Intrinsic semiconductors are made of a pure substance, with no added impurities. The most
common materials used as intrinsic semiconductors are silicon (Si) and germanium (Ge).
Intrinsic semiconductors, charge carriers (electrons and holes) are generated by thermal excitation.
When an electron gains enough thermal energy, it can jump from the valence band to the conduction
band, leaving behind a "hole" in the valence band. These holes act as positive charge carriers. When an
electron jumps from the valence band to the conduction band, it creates an electron-hole pair. In an
Downloaded from Ktunotes.in
