Why is carbon not used as a semiconductor?

Answer 1

semiconductors are silicon and germanium. they are like metals but their highest occupied electron shells/orbitals do not overlap. they require a little energy to exite electrons into the conduction band.

Small amounts of group 3 or 5 elements can be changed to dramatically alter conductivity.

the structure of carbon allotropes, such as diamond and graphite, do not allow this. Diamond is a covalent network with no free electrons. Graphite is layers of hexagonal carbon networks with electrons allowed to flow in one directing only. Adding these metal impurities, if it can be done easily, will not have the same effect

Answer 2

Answer:

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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.

http://wiki.answers.com/Why_carbon_does_not_use_as_a_semiconductor#ixzz1Zq861YTx

Answer 3

Actually carbon in the form of diamond, nanotubes, or graphene is a better semiconductor than silicon it is just more difficult and thus more expensive to process into devices. The maximum operating junction temperature for carbon semiconductor should be about 600C compared to silicon at only 150C.