Why carbon does not use as a semiconductor?

Answer 1

I don't really know too much about tin, but I can speak about carbon and semiconductors in general.

To be a semiconductor the solid must have (at least) two characteristics: the bonding and anti-bonding orbitals must form a pair of delocalized bands, where the density of states in these bands is very high (such that it approximates a continuum of states when plotted vs. energy). Secondly, the band-gap, or difference in energy between these two states must relatively small. This gap is what corresponds to the HOMO-LUMO gap in molecular species. This gap is generally on the order of 0.5 eV to 3.5 eV for semiconductors -- large enough that room temperature thermal energy will not excite electrons across this energy gap (which would make it metallic), but not so large that the material is considered an insulator.

Carbon, when bonding does not usually meet either criteria. For one, in a typical molecular species, there is not a large enough repeating and regular structure to build up these bands of energy levels. But in structures such as diamond, where a very regular and large repeating structure does exist, the band gap is so large that it is an insulator. However there are forms of carbon which are considered semiconducting, and are generally known as "organic semiconductors. There are many types, but most of them are large polymers with alternating double bonds for delocalized pi-bonding systems to create a high density of states with a small HOMO-LUMO gap. Although not yet available commercially, organic semiconductors are commonly made into solar cells, where their semiconducting properties allow the polymers to absorb light and conduct charges across an interface for efficient charge separation. Thiophenes, anthracenes and other polymeric systems with large conjugated pi-systems all have semiconducting properties.

If you are interested in knowing much more about semiconductor basic physics and chemistry, you can contact me (JEK) through my bio page on this site and I can give you several excellent references to introduce you to the subject!

Answer 2

Electricity can conduct through carbon, but carbon does have a significant resistance, and much of the electrical energy will be lost as heat energy when it passes through carbon and it forms diamond crystal structure so when we add impurity atoms it will not make any significant change...+

Carbon is not used as semiconductor it has 4 valence electrons in it valence shell but the energy gap is very small it will conduct electricity even at room temperature ,the size of carbon is very small . It depends upon the structure of carbon.In case of germanium and silicon they have d orbits in the outer shell and they have greater mobility.

I think we need to give much energy for conduction because the valance electrons are very close to nucleus and on the case of Silicon and germanium they are so far from nucleus as compared to carbon.and i think it has very hard crystalline structure so change in structure(doping) is harder than other semiconductor little a bit .but latest semiconductor Graphene is the another form of carbon (upper layer) and Konstantin Novoselove and Andre Geim won the Nobel prize in physics in 2010 for this semiconductor.and it is very superior than our convention semiconductor (compound+elemental).another semiconductor Molybdnite is more superior than Graphene it has very high mobility and energy gap(1.8eV Approx) in comparison of others.for more detail about these semiconductor visit

sujeetsinghec.blogspot.com

Answer 3

it has a large resistivityaa as compared to si and Ge.and also its conductivity is also large . there have 4 valence electron which are near to nucleus so it required large energy to move electron.so by these reason we are not used as semiconductor.......

Answer 4

If you take the normal use of semi-metal- (comes from band theory) graphite is a semi-metal- diamond is not. If you equate the terms semi-metal and metalloid- then no allotrope of carbon could be considered a metalloid.

Answer 5

Carbon doesn't have the non-linear voltage/current relationship that defines a diode.

Electrically, carbon acts as a simple resistor, which is the main reason that most resistors

are constructed of carbon.

Answer 6

The resistance of a semiconductor depends on the amplitude and polarity

of the applied voltage.

The resistance of carbon doesn't depend on the amplitude or the polarity

of the applied voltage.

Answer 7

Because due it's small in size carbon experience high covalent bond hence high amount of energy required to break it compared to si and Ge in which they are large in size hence small amount of energy required to break there bond to give free electron

Answer 8

Carbon is not used in electronic devices because it is difficult to modify its natural properties as opposed to silicon.

Answer 9

because it is very unstable