Method for producing two-dimensionally patterned carbon nanotube and two-dimensionally patterned carbon nanotube

Abstract

Disclosed are a method for producing a carbon nanotube (CNT) whereby, in the local synthesis of CNTs, a high resolution, a low cost, easiness in production and mass production capability can be established at the same time; and a two-dimensionally patterned CNT obtained thereby. Specifically disclosed are a method for producing a two-dimensionally patterned CNT which comprises: A) a step for preparing a substrate; B) a step for forming a first two-dimensional pattern, which consists of hydrophobic surface and hydrophilic surface, on the substrate by means of 1) masking and electromagnetic wave irradiation, or 2) electron beam irradiation; C) a step for applying a catalyst-containing solution to the substrate having the first two-dimensional pattern and forming a second two-dimensional pattern depending on the presence or absence of the catalyst; and D) a step for forming by ACCVD a two-dimensional pattern of the CNT on the thus obtained substrate; a substrate; and a structure comprising a two-dimensionally patterned CNT on the aforesaid substrate.

1 . A method for producing a two-dimensionally patterned carbon nanotube, comprising the steps of:
 A) preparing a substrate;   B) 1) covering the substrate with a mask and irradiating the substrate with an electromagnetic wave through the mask, in the presence or absence of electromagnetic wave irradiation with or without the mask, or
 2) irradiating the substrate with an electron beam in the presence or absence of the electron beam irradiation, to form a first two-dimensional pattern consisting of a hydrophobic surface and a hydrophilic surface on a surface of the substrate; 
   C) applying a catalyst-containing liquid on the substrate having the first two-dimensional pattern, to form a second two-dimensional pattern, depending on the presence or absence of the catalyst, wherein the hydrophilic surface retains the catalyst and the hydrophobic surface does not retain the catalyst; and   D) forming a carbon nanotube on the resulting substrate by chemical vapor deposition under the presence of a carbon source, wherein the carbon nanotube is formed on the surface retaining the catalyst and any carbon nanotube is not formed on the surface which does not retain the catalyst.   
     
     
         2 . The method according to  claim 1 , wherein the substrate in the step A) is A′) a substrate having the hydrophobic surface on its entire surface; and
 the step B) is a step B)-1), and the step B)-1) is a step B)-1′) of covering the hydrophobic surface with a mask and irradiating the hydrophobic surface with an electromagnetic wave through the mask, thereby changing the hydrophobic surface which is not covered with the mask into a hydrophilic surface, and remaining a portion which is covered with the mask as the hydrophobic surface, to form the first two-dimensional pattern. 
 
     
     
         3 . The method according to  claim 1 , wherein the substrate in the step A) is A′) a substrate having the hydrophobic surface on its entire surface; and
 the step B) is a step B)-2), and the step B)-2) is a step B)-2′) of irradiating the hydrophobic surface with an electron beam, thereby changing a portion irradiated with the electron beam into a hydrophilic surface, and remaining a portion which is not irradiated with the electron beam as the hydrophobic surface, to form the first two-dimensional pattern. 
 
     
     
         4 . The method according to  claim 1 , wherein the substrate having the hydrophobic surface on its entire surface in the step A′) is prepared by a step E)-1) of preparing a substrate having a hydrophilic surface on its entire surface and then E)-2) applying a surface hydrophobication solution on the hydrophilic surface thereby to change an entire portion of the hydrophilic surface into a hydrophobic surface. 
     
     
         5 . The method according to  claim 4 , wherein the step E)-1) further comprises a step E)-1)-1) of cleaning the surface of the substrate having the hydrophilic surface on its entire surface. 
     
     
         6 . The method according to  claim 5 , wherein the step E)-1)-1) further comprises a step a) of sintering the substrate having the hydrophilic surface on its entire surface under the presence of oxygen at 300° C. or more. 
     
     
         7 . The method according to  claim 5 , wherein the step E)-1)-1) further comprises a step b) of cleaning the substrate having the hydrophilic surface on its entire surface with a mixture solution of a NH 3  aqueous solution and a hydrogen peroxide aqueous solution at 80° C. or less. 
     
     
         8 . The method according to  claim 4 , wherein the surface hydrophobication solution comprises a silane compound represented by R 1 —Si—X 1   m X 2   (3-m) , wherein R 1  represents an organic group having C10-20 linear or branched chain; X 1  and X 2  each represents —OCH 3  or —Cl; and m represents an integer of 0 to 3. 
     
     
         9 . The method according to  claim 1 , wherein the substrate prepared in the step A), A′), or E)-1) is Si, quartz, crystal, or sapphire each having SiO 2  on its surface. 
     
     
         10 . The method according to  claim 1 , wherein a hydrophilicity of the hydrophilic surface in the step B) is represented by a water contact angle of 10° or less. 
     
     
         11 . The method according to  claim 1 , wherein a hydrophobicity of the hydrophobic surface in the step B) is represented by a water contact angle of 90° or more. 
     
     
         12 . The method according to  claim 1 , wherein the electromagnetic wave irradiation in the step B)-1) is UV ray irradiation. 
     
     
         13 . The method according to  claim 1 , wherein the catalyst-containing liquid in the step C) is an ethanol solution of a molybdenum salt and/or an ethanol solution of a cobalt salt. 
     
     
         14 . The method according to  claim 1 , further comprising a step F) of sintering the substrate having the second two-dimensional pattern after the step C) and before the step D). 
     
     
         15 . The method according to  claim 14 , wherein the step F) is performed under atmospheric environment at 300° C. or more. 
     
     
         16 . The method according to  claim 1 , wherein the carbon source in the step D) is a lower alcohol, and the chemical vapor deposition is performed under a reduced pressure and a vapor deposition temperature of 500° C. or more. 
     
     
         17 . The method according to  claim 1 , wherein the carbon nanotube is a few-walled carbon nanotube. 
     
     
         18 . The method according to  claim 1 , wherein the carbon nanotube is a single-walled carbon nanotube. 
     
     
         19 . The method according to  claim 1 , wherein an axis direction of the carbon nanotube is aligned perpendicular to the substrate. 
     
     
         20 . The method according to  claim 1 , wherein an axis direction of the carbon nanotube is aligned parallel to the substrate. 
     
     
         21 . The method according to  claim 1 , wherein the carbon nanotube has an average diameter of 3 nm or less. 
     
     
         22 . The method according to  claim 1 , wherein the two-dimensionally patterned carbon nanotube has 300 nm or less of a possible-smallest-line-width at a portion where the carbon nanotube is disposed, while a possible-smallest-line-width at a portion where the carbon nanotube is not disposed is 300 nm or less. 
     
     
         23 . A structure comprising a substrate and a two-dimensionally patterned carbon nanotube formed on the substrate. 
     
     
         24 . The structure according to  claim 23 , wherein the substrate is Si, quartz, crystal, or sapphire each having SiO 2  on its surface. 
     
     
         25 . The structure according to  claim 23 , wherein the carbon nanotube is a few-walled carbon nanotube. 
     
     
         26 . The structure according to  claim 23 , wherein the carbon nanotube is a single-walled carbon nanotube. 
     
     
         27 . The structure according to  claim 23 , wherein an axis direction of the carbon nanotube is aligned perpendicular to the substrate. 
     
     
         28 . The structure according to  claim 23 , wherein an axis direction of the carbon nanotube is aligned parallel to the substrate. 
     
     
         29 . The structure according to  claim 23 , wherein the carbon nanotube has an average diameter of 3 nm or less. 
     
     
         30 . The structure according to  claim 23 , wherein the two-dimensionally patterned carbon nanotube has 300 nm or less of a possible-smallest-line-width at a portion where the carbon nanotube is disposed, while a possible-smallest-line-width at a portion where the carbon nanotube is not disposed is 300 nm or less.