Graphene semiconductor and electrical device including the same
A graphene semiconductor including graphene and a metal atomic layer disposed on the graphene, wherein the metal atomic layer includes a metal, which is capable of charge transfer with the graphene.
1. A graphene semiconductor comprising:
graphene;
a metal atomic layer disposed on the graphene; and
a first oxide layer disposed on the metal atomic layer,
wherein the metal atomic layer comprises an alkali metal, which is capable of charge transfer with the graphene,
the first oxide layer comprises an alkali metal oxide,
the alkali metal oxide is an oxidation product of a surface of the metal atomic layer, and
a thickness of the first oxide layer is in a range of about 1 nanometer to about 100 nanometers.
2. The graphene semiconductor of claim 1 , wherein the metal atomic layer comprises sodium.
3. The graphene semiconductor of claim 1 , wherein the metal atomic layer is disposed on a surface of the graphene.
4. The graphene semiconductor of claim 1 , wherein the metal atomic layer comprises a two-dimensional film structure.
5. The graphene semiconductor of claim 1 , wherein the metal atomic layer has a form of a film, a nanorod, a nano-cluster, or a combination thereof.
6. The graphene semiconductor of claim 1 , wherein the metal atomic layer occupies about 30% to about 99% of an entire surface of the graphene.
7. The graphene semiconductor of claim 1 , wherein the graphene semiconductor has a band gap of about 0.4 electron volt or more.
8. The graphene semiconductor of claim 1 , wherein the graphene semiconductor has a band gap of about 0.45 electron volt to about 0.8 electron volt.
9. The graphene semiconductor of claim 1 further comprising a second oxide layer disposed on the first oxide layer.
10. An electrical device comprising the graphene semiconductor of claim 1 .
11. The electrical device of claim 10 , wherein the electrical device is a sensor, a bipolar junction transistor, a field effect transistor, a heterojunction bipolar transistor, a single electron transistor, a light-emitting diode, or an organic electroluminescent diode.
12. A method of selecting a band gap of graphene, the method comprising:
disposing graphene on a substrate;
disposing a metal atomic layer comprising an alkali metal on the graphene; and
forming a first oxide layer having a thickness in a range of about 1 nanometer to about 100 nanometers on the graphene by oxidizing a surface of the metal atomic layer to select the band gap of the graphene.
13. The method of claim 12 , further comprising disposing a second oxide layer on the first oxide layer.
14. The method of claim 12 , further comprising repeating the disposing and the forming to dispose an additional metal atomic layer on the graphene and form an additional oxide layer on the additional metal atomic layer by oxidizing the additional metal atomic layer.