Polycrystalline cuprous oxide nanowire array production method using low-temperature electrochemical growth

Abstract

There are provided a monocrystalline copper oxide (I) nanowire array manufacturing method using low-temperature electrochemical growth, and more particularly, to a manufacturing method allowing easy vapor deposition at low temperatures and also a monocrystalline copper oxide (I) nanowire array manufacturing method using low-temperature electrochemical growth which retains characteristics such as large-area growth, high-crystallinity nanowire, uniform radial distribution, easy length, radius adjustment, and the like. A monocrystalline copper oxide (I) nanowire array manufacturing method of the present invention includes a step of manufacturing a nanopore alumina layer (anodized alumina (AAO)) from a high-purity aluminum (Al) sheet by using a two-step anodic oxidation method; and a step of manufacturing a monocrystalline copper oxide (I) nanowire array by using the nanopore alumina layer as a nanopore molding flask by means of a low-temperature electrochemical growth method.

1 . A monocrystalline copper oxide (I) nanowire array manufacturing method using low-temperature electrochemical growth, the method comprising:
 a step of manufacturing a nanopore alumina layer (anodized alumina (AAO)) from a high-purity aluminum (Al) sheet by using a two-step anodic oxidation method; and   a step of manufacturing a monocrystalline copper oxide (I) nanowire array by using the nanopore alumina layer as a nanopore molding flask by means of a low-temperature electrochemical growth method.   
     
     
         2 . The method of  claim 1 , wherein the step of manufacturing a nanopore membrane from a high-purity aluminum (Al) sheet by using a two-step anodic oxidation method includes:
 a step of electrolytically polishing the high-purity aluminum sheet by applying direct current voltage thereto in an electrolytic polishing solution;   a step of primary anodic oxidation for anodically oxidizing the electrolytically polished aluminum sheet in a sulfuric acid (H 2 SO 4 ) aqueous solution or an oxalic acid (H 2 C 2 O 4 ) aqueous solution;   a step of etching and removing a porous alumina layer formed by the primary anodic oxidation with a mixed solution of phosphoric acid (H 3 PO 4 ) and chromic acid (CrO 3 );   a step of secondary anodic oxidation for anodically oxidizing the alumina sheet, from which an alumina oxide layer is removed, in a sulfuric acid (H 2 SO 4 ) aqueous solution or an oxalic acid (H 2 C 2 O 4 ) aqueous solution;   a step of protecting the nanopore alumina layer from an etching process by coating a mixture of nitrocellulose and polyester thereon after the step of secondary anodic oxidation;   a step of forming a nanopore channel by etching the nanopore alumina layer at a predetermined temperature with a phosphoric acid (H 3 PO 4 ) solution; and   a step of depositing a platinum (Pt) layer or a gold (Au) layer on one side surface of the nanopore membrane.   
     
     
         3 . The method of  claim 2 , wherein the electrolytic polishing solution includes chloric acid (HClO 4 ) and ethanol at a volume ratio of 1:4. 
     
     
         4 . The method of  claim 2 , wherein the step of electrolytically polishing includes electrolytically polishing the high-purity aluminum sheet at a temperature of 10° C. for 4 minutes by applying direct current voltage of +20 V thereto in an electrolytic polishing solution. 
     
     
         5 . The method of  claim 2 , wherein the step of primary anodic oxidation includes anodically oxidizing the electrolytically polished aluminum sheet at a temperature of 10° C. for 12 hours by applying voltage of +20 V thereto in a 0.3 M sulfuric acid (H 2 SO 4 ) aqueous solution or a 0.3 M oxalic acid (H 2 C 2 O 4 ) aqueous solution. 
     
     
         6 . The method of  claim 2 , wherein the step of etching and removing a porous alumina layer formed by the primary anodic oxidation with a mixed solution of phosphoric acid (H 3 PO 4 ) and chromic acid (CrO 3 ) includes etching and removing a porous alumina layer formed by the primary anodic oxidation at a predetermined temperature with a mixed solution of phosphoric acid (H 3 PO 4 ) and 1.8 wt % of chromic acid (CrO 3 ). 
     
     
         7 . The method of  claim 2 , wherein the step of secondary anodic oxidation includes anodically oxidizing the aluminum sheet, from which an alumina oxide layer is removed, at a temperature of 10° C. for a desired time period by applying voltage of +20 V thereto in a 0.3 M sulfuric acid (H 2 SO 4 ) aqueous solution or a 0.3 M oxalic acid (H 2 C 2 O 4 ) aqueous solution. 
     
     
         8 . The method of  claim 2 , wherein the step of protecting the nanopore alumina layer from an etching process includes protecting the nanopore alumina layer from an etching process by coating a mixture of nitrocellulose and polyester thereon after the step of secondary anodic oxidation. 
     
     
         9 . The method of  claim 2 , wherein the step of forming a nanopore channel includes forming a nanopore channel by etching the nanopore alumina layer with 5 wt % of a phosphoric acid (H 3 PO 4 ) solution at a temperature of 30° C. for 15 minutes. 
     
     
         10 . The method of  claim 2 , wherein the step of depositing a Pt layer or an Au layer includes depositing a platinum (Pt) layer or a gold (Au) layer on one side surface of the nanopore membrane to a thickness of 200 nm or more. 
     
     
         11 . The method of  claim 1 , wherein the step of manufacturing a monocrystalline copper oxide (I) nanowire array by using the nanopore alumina layer as a nanopore molding flask includes:
 a step of manufacturing an electrochemical deposition solution by mixing copper nitrate hydrate (Cu(NO 3 ) 2 2.5H 2 O) and hexamethylenetetramine;   a step of stirring the electrochemical deposition solution and heating the electrochemical deposition solution in a boiling water bath;   a step of stirring the electrochemical deposition solution at a predetermined temperature;   a step of applying a predetermined current density to the nanopore molding flask in an electrochemical reaction solution;   a step of washing an electrochemically grown nanowire with ethanol and deionized water and drying the nanowire;   a step of performing a heat treatment to improve crystallinity of the nanowire; and   a step of removing a nanopore membrane with an NaOH aqueous solution.   
     
     
         12 . A monocrystalline copper oxide (I) nanowire array manufactured by the manufacturing method according to  claim 1 .