Reactor and system for fabrication of free-standing two-dimensional nanostructures using plasma technology
The present invention relates to a process, reactor and system to produce self-standing two-dimensional nanostructures, using a microwave-excited plasma environment. The process is based on injecting, into a reactor, a mixture of gases and precursors in stream regime. The stream is subjected to a surface wave electric field, excited by the use of microwave power which is introduced into a field applicator, generating high energy density plasmas, that break the precursors into its atomic and/or molecular constituents. The system comprises a plasma reactor with a surface wave launching zone, a transient zone with a progressively increasing cross-sectional area, and a nucleation zone. The plasma reactor together with an infrared radiation source provides a controlled adjustment of the spatial gradients, of the temperature and the gas stream velocity.
1 . A microwave plasma reactor for the production of two dimensional structures of graphene or graphene derivatives, comprising:
a body, the body being hollow, the body comprises an admission part for admission of a mixture of at least one inert gas and at least one precursor;
the body including a plasma creation surface wave launching part where surface waves are launched,
the body including a precursor constituents nucleation part and a transient section, the transient section having a first end and a second end connected, respectively, to the surface wave launching part and to the nucleation part, the transient section providing fluid communication between the plasma creation surface wave launching part and the precursor constituents nucleation part,
wherein the plasma creation surface wave launching part, the transient section and the precursor constituents nucleation part define, respectively, in the body three inner zones of operation, wherein the first end of the transient section has a cross-sectional area which is smaller than a cross-sectional area of the second end of the transient section, wherein the cross-sectional area of the transient section progressively increases from the first end to the second end and plasma is produced from the surface waves propagating from the plasma creation surface wave launching part and wherein the reactor produces the two dimensional structures of graphene or graphene derivatives.
2 . The plasma reactor according to claim 1 , wherein the plasma creation surface wave launching part, the transient section and the precursor constituents nucleation part are integrally connected to one another, forming a single piece.
3 . The plasma reactor according to claim 1 , wherein the hollow body is formed of a dielectric material selected from the group consisting of quartz, sapphire, alumina and combinations thereof.
4 . The plasma reactor according to claim 1 , the admission part being integrated in a surface wave launching part or the admission part being attached to the surface wave launching part through connections.
5 . A system for producing two dimensional structures of graphene or graphene derivatives comprising:
a plasma reactor as claimed in claim 1 , and
at least, one infrared radiation source on the outside of the body, arranged to irradiate one of the inner zones being defined by the precursor constituents nucleation part of the body.
6 . The system according to claim 5 , further comprising, a cooling device on the outside of the body, wherein the cooling device is arranged to cool, at least, one of the inner zones defined by the transient section of the body.
7 . The system according to claim 6 , wherein the cooling device is operable in a temperature range comprised between 40 to 220° C.
8 . The system according to claim 6 , further comprising, a source of ultraviolet radiation on the outside of the body, arranged to irradiate, at least, one of the inner zones defined by the precursor constituents nucleation part of the body.
9 . The system according to claim 7 , further comprising, a source of ultraviolet radiation on the outside of the body, arranged to irradiate, at least, the one of the inner zones defined by the nucleation part of the body.