An n-type Semiconductor is_________


An n-type Semiconductor is_________

  1. Positively Charged
  2. Negatively Charged
  3. Electrically Neutral
  4. None of the above

The correct option is(3)
An n-type Semiconductor is electrically neutral because the process of doping, which introduces extra charge carriers, does not alter the overall charge balance within the semiconductor material.


Here’s a step-by-step explanation:

  1. Intrinsic Semiconductor: An intrinsic semiconductor, typically made from silicon or germanium, is electrically neutral with an equal number of protons (positive charges) in the nuclei and electrons (negative charges) surrounding them.
  2. Doping Process: To create an n-type semiconductor, dopant atoms with more valence electrons than the semiconductor material (typically five valence electrons, such as phosphorus or arsenic) are added to the semiconductor lattice. This process is called doping.
  3. Extra Electrons: In the case of n-type doping, the dopant atoms replace some of the semiconductor atoms in the lattice. Each dopant atom has one more electron than is needed for the bond structure with the neighboring semiconductor atoms. For example, phosphorus has five electrons in its outer shell, but only four are needed to bond with the surrounding silicon atoms. The fifth electron is excess and is easily available for electrical conduction.
  4. Charge Neutrality: The overall semiconductor remains electrically neutral despite these extra electrons contributing to electrical conductivity. This is because each extra negative charge (electron) introduced by the dopant is balanced by the positive charge of the extra proton in the nucleus of the dopant atom. Therefore, the addition of electrons does not change the overall charge balance; it only provides carriers that can move freely and contribute to conduction.

Thus, the semiconductor maintains its electrical neutrality because the number of positive charges (protons) still equals the number of negative charges (electrons) despite adding dopants that change the electrical conductivity characteristics.

Q1. The forbidden gap for Germanium is_______

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