what do we mean by 'hole' in case of a semiconductor?

Answer 1

I think its energy gap. I think doping fills it up. Doesn't it?

Answer 2

in solid-state physics, a phenomenon produced by the movement of valence electrons through certain metals and semiconductors, resulting in the creation of a vacancy in a corresponding energy state. Each vacancy, or hole, represents the absence of an electron from an accessible energy state in the solidand, thus, a centre of positive charge.

According to the band theory of solids, electrons within a solid have energies at only certain discrete levels. These discrete levels combine to form groups of energy levels, or bands. The band behaves as though each level from which an electron was removed contains a positive charge, or hole.

Holes are often deliberately introduced into a solid in order to increase its ability to carry an electric current. Through a processcalled doping, small quantities of impurity atoms are added to an otherwise pure semiconductor. In p-type semiconductors the impurity atoms contain fewer valence electrons than the atoms in the solid.

A p-type semiconductor can be formed by the introduction of boron (B) atoms into a crystal of germanium (Ge). A boron atom contains three valence electrons and a germanium electron has four valence electrons, so every boron atom added to the semiconductor creates a deficiency of one electron as well as a hole of positive charge. This hole must then be filled by the movement of another electron from within the crystal, which, in turn, creates a second hole. As electrons fill some holes while creating others, the resulting movement of positive charge encourages conduction

Answer 3

All metals have free electrons which are not bound to the atoms.

Conduction in metals is due to these free electrons.

Silicon (semiconductor) atoms have four valence electrons. They are bound to the atom of silicon. Silicon atoms do not have free electrons.

Near absolute zero silicon is a non conductor of current.

However, with rise of temperature, some of the valence electrons are freed from the bonds of the atoms. Now the material is capable of conduction.

The vacancy of an electron in the bonds of an atom is called hole. The freed electrons, if they loose their energy will be pulled by the hole. Therefore it is equivalent to a positive charge.

In semiconductors (silicon), conduction is due to both electrons and holes.

In metals there are no holes and conduction is due to electrons only.

Answer 4

Pure silicone is an insulator - the crystalline structure is both electrically neutral (the same number of electrons and protons) and held tightly in place by the crystalline structure.
When the pure silicone is intentionally doped with boron, the crystaline structure is maintained, but the boron atom is electron deficient compared to the silicone and this creates a "hole" where a pure silicone atom would normally have an electron. This electron deficiency makes the material a P type semiconductor - i.e. it "needs" extra electrons to fill in the "holes" in the crystal.

Answer 5

Hole is a place where an electron is missing, causing a positively charged space.

When the charge on two adjacent regions is one way the electrons and holes move away from the barrier, and no current flows.

In the other polarity, the two sets of charges move toward the barrier, and electrons can migrate across the barrier in the form of current flow.

Answer 6

It is the absence of an electron, it can be thought of as a positive charge.

Answer 7

holes are the charge carriers.they can be majority or minority charge carrier depending upon the polarity of the pn junctions

Answer 8

An absence of an electron.