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#carrier concentration

2 public questions tagged with this topic.

Doping, Charge Carriers and Conductivity

In an extrinsic semiconductor, the minority carrier concentration is reduced due to:

**Doping** is adding impurity to pure semiconductor to increase carriers, pentavalent (P, As, Sb) donates extra electron, 1 ppm doping in Ge with 4×10²⁸ atoms/m³ gives donor density N_d = 4×10²⁸×10⁻⁶ =4×10²² m⁻³ for 1 ppm, acceptor atoms p-type trivalent B, Al, Ga. Overall charge neutrality maintained because donor ion core positive but electron negative, net neutral. Doping increases majority carriers (electrons in n-type, holes in p-type), enhancing recombination with minority carriers, thus reducing their concentration indirectly. Substituting values gives Increased recombination, which mat

Ref: NCERT > Physics Book > Electronic Devices > Doping, Charge Carriers and Conductivity

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Semiconductors, Types and Energy Bands

In an intrinsic semiconductor, the number of charge carriers increases with:

**Semiconductor properties** distinguish from conductors and insulators by temperature dependence and doping response. At 0 K intrinsic acts as insulator, conductivity due to thermally generated electron-hole pairs, number of outer electrons 4 for Si/Ge forming covalent bonds, each atom shares electrons, crystal with N atoms has 4N valence electrons, 2N bonds. In an intrinsic semiconductor, thermal energy excites electrons from valence to conduction band, creating electron-hole pairs, and this process increases with rising temperature. Substituting values gives Increase in temperature, which m

Ref: NCERT > Physics Book > Electronic Devices > Semiconductors, Types and Energy Bands

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