Homojunction
Encyclopedia
A homojunction is a semiconductor
interface that occurs between layers of similar semiconductor material, these materials have equal band gap
s but typically have different doping
. In most practical cases a homojunction occurs at the interface between an n-type
(donor
doped) and p-type
(acceptor
doped) semiconductor such as silicon
, this is called a pn junction. This is not a necessary condition as the only requirement is that the same semiconductor (same band gap
) is found on both sides of the junction, in contrast to a heterojunction
.
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
interface that occurs between layers of similar semiconductor material, these materials have equal band gap
Band gap
In solid state physics, a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference between the top of the valence band and the...
s but typically have different doping
Doping (semiconductor)
In semiconductor production, doping intentionally introduces impurities into an extremely pure semiconductor for the purpose of modulating its electrical properties. The impurities are dependent upon the type of semiconductor. Lightly and moderately doped semiconductors are referred to as extrinsic...
. In most practical cases a homojunction occurs at the interface between an n-type
N-type semiconductor
N-type semiconductors are a type of extrinsic semiconductor where the dopant atoms are capable of providing extra conduction electrons to the host material . This creates an excess of negative electron charge carriers....
(donor
Donor (semiconductors)
In semiconductor physics, a donor is a dopant atom that, when added to a semiconductor, can form n-type regions.For example, when silicon , having four valence electrons, needs to be doped as an n-type semiconductor, elements from group V like phosphorus or arsenic can be used because they have...
doped) and p-type
P-type semiconductor
A P-type semiconductor is obtained by carrying out a process of doping: that is, adding a certain type of atoms to the semiconductor in order to increase the number of free charge carriers ....
(acceptor
Acceptor (semiconductors)
In semiconductor physics, an acceptor is a dopant atom that when added to a semiconductor can form p-type regions.For example, when silicon , having four valence electrons, needs to be doped as a p-type semiconductor, elements from group III like boron or aluminium , having three valence...
doped) semiconductor such as silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
, this is called a pn junction. This is not a necessary condition as the only requirement is that the same semiconductor (same band gap
Band gap
In solid state physics, a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference between the top of the valence band and the...
) is found on both sides of the junction, in contrast to a heterojunction
Heterojunction
A heterojunction is the interface that occurs between two layers or regions of dissimilar crystalline semiconductors. These semiconducting materials have unequal band gaps as opposed to a homojunction...
.
External links
- Solar cell structures (EERE)