KR20090069911A - Hetero-epitaxial fabrication of coaxial nanorods - Google Patents

Abstract

A hetero-epitaxial structure and a method for manufacturing nanowires with heterodoping structures are provided to enable a doping material to be partly added to nanowires and to join different metal oxide nanowires together. A method for manufacturing nanowires with heterodoping structures comprises the following steps of: coating a substrate(6) with a seed layer(7) of RF sputter; forming a photoresist pattern in order to expose some parts of the seed layer to the outside; and growing zinc oxide nanowire on the top of the exposed seed layer through photoresist patterning. A zinc ion-containing material with NH4OH is used for hydrothermal synthesis of zinc oxide nanowire. The hydrothermal synthesis is performed under a pH range of 10 or greater at 60°C or higher. A material containing Fe ion and Ga ion is added to the synthetic solution to manufacture doped zinc oxide nanowire.

Description

Manufacturing method of nanowire with heterostructure and hetero doped structure stacked in growth direction {Hetero-epitaxial fabrication of coaxial nanorods}

The present invention relates to a method for manufacturing one nanowire by sequentially growing nanowires to which different types of metal oxides and other doping materials are added for application to nanodevices. For example, a method of manufacturing a heterostructured nanowire through a series of processes such as manufacturing a zinc oxide nanowire, which is a metal oxide semiconductor material at the bottom, and further growing a tin oxide nanowire at the top.

Metal oxide semiconductors ZnO, SnO2 and the like have been reported as a material that is applied as a variety of devices applying the optical and electrical properties as a semiconductor device has been reported the synthesis of these metal oxide nanowires. In the case of metal oxide nanowires, hydrothermal synthesis based on solution synthesis, sol-gel method, and vaporliquidsolid (VLS) based on synthesis in the gas phase are known. Nanowires have a considerable surface area to volume ratio, which is increasing interest as a gas sensor and an optical device. To achieve such a device, a technology for selectively aligning nanowires and manufacturing various nanostructures is required. Accordingly, the present invention relates to the production of heterostructures and heterostructures in which heterogeneous metal oxides or other doping materials are applied to a single nanowire in a structure fabrication technique for device fabrication of nanowires.

Generally, nanowires are made of a single kind of metal oxide, and impurities are added to impart performance to the device. The present invention relates to the fabrication of heterostructured nanowires for device applications of metal oxide nanowires. The heterostructured nanowire may be configured by connecting or stacking two metal oxide nanowires on one nanowire, and may also be configured by adding another doping material to one upper and lower portion of the nanowire. However, when the nanowires are synthesized on the substrate through known hydrothermal synthesis and vapor phase methods, and then resynthesized by applying another material or a doping material on the grown nanowires, they are deposited for growth on the substrate in addition to the first grown nanowires. Not only do not control the growth of additional nanowires over the seed layer, but also difficulty in manufacturing uniform nanowires due to the inability to control the increase in the density and diameter of the nanowires with the growth time used for hydrothermal synthesis. In addition, the growth in the lateral direction as well as the growth of additional nanowires in the vertical direction can not be controlled. Therefore, in the case of epitaxy growth of nanowires through the vapor phase method, the nanowires may not grow vertically and form a kind of branch shape or a film may be formed on the side of the first synthesized nanowire. Accordingly, the present invention was derived for the fabrication of heterostructured nanowires in which nanowire structures are stacked in a vertical direction uniformly with control of diameter and density of nanowires.

The present invention relates to a heterostructure or a route fabrication method that is grown in a form in which nanowires of uniform heterostructures are bonded to each other. The nanowires can be grown primarily by hydrothermal synthesis using templates with other nano-sized pore as a template for control, and then added on top of the existing nanowires using hydrothermal synthesis using growth solutions containing other precursors. By growing epitaxial lines, nanowires with the desired heterostructure can be fabricated.

The present invention can be applied to the structure fabrication technology required for the device utilization of the nanowires as a method of manufacturing a nanowire of a heterostructure, it is possible to partially add a doping material and heterogeneous metal oxide nanowires to the nanowires.

The present invention relates to a method for producing heterostructured nanowires grown in a form in which heterostructures of heterostructures are uniformly bonded. First, seed layers for nanowire growth are deposited on the substrate through RF sputtering and sol-gel methods. Application of the seed layer for growth includes the case of a catalyst such as Au for nanowire growth. After that, a photoresist pattern is manufactured by using a lithography process above the nanowire height. The photoresist pattern will serve as a template for controlling growth growth and lateral growth of the nanowires. From the seed layer exposed through the photoresist pattern, the nanowires are first grown by hydrothermal synthesis and other synthetic methods, and additionally grown using other precursors to epitaxially grow new nanowires over the existing nanowires to achieve the desired heterostructure. Nanowires can be produced.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the following description is only to explain the present invention in detail, and the scope of the present invention is not limited by the following description, and the zinc oxide hydrothermal synthesis method is shown as an example of a method for synthesizing heterostructured nanowires. Represented nanowires with Fe and Ga applied as doping materials, respectively.

After the seed layer 13 is coated on the substrate 12 such as silicon by RF sputtering, a photoresist pattern is manufactured to expose a part of the seed layer. Accordingly, as shown in FIG. 3, the zinc oxide nanowires are grown on the seed layer exposed to the selective region by patterning the photoresist 14. Zinc oxide nanowire hydrothermal synthesis is to use a material containing zinc ions such as zinc sulfate, zinc nitrate, and this OH ^- The NH ₄ solution using a combination of a solution of OH such as zinc nanowire growth pH range of 10 or more oxide containing the After the preparation can be synthesized at 60 ℃ or more process temperature conditions. A doped zinc oxide nanowire is prepared by adding a material containing metal ions such as Fe and Ga to the synthesis solution.

Next, a new hydrothermal synthesis step is introduced onto the first grown nanowire to grow heterologous nanowires as shown in FIG. 4. At this time, using the doped zinc oxide nanowires synthesized in the step of Figure 3 as a substrate to reuse the synthesis method of the nanowires. In this case, the synthesis method used does not need to be identical to the steps of FIG. 3, and may include other sol-gel methods and vapor phase methods. Also, in the case of the nanowires, materials different from those of FIG. 3 may be used, for example, tin oxide nanowires. In the case of hydrothermal synthesis, a growth solution including other doping materials is reprepared, and a heterogeneous doping structure is manufactured through the previous solution preparation method and process conditions. For example, if the Fe-doped zinc oxide nanowires are manufactured in FIG. 3, the Ga-doped zinc oxide nanowires are laminated in FIG. 4 by hydrothermal synthesis with other doping materials, Ga.

After that, the patterned photoresist 15 or other template is removed from the substrate, and a conceptual diagram of the remaining nanowires of the hetero-doped structure grown on the substrate remains.

1 is a conceptual view in which the seed layer 13 is coated on the silicon substrate 12 using RF sputtering or the like.

2 is a conceptual diagram in which a photoresist 14 is covered on a silicon substrate 12 to which a seed layer 13 is applied.

3 is a conceptual diagram in which nanowires are grown in selective regions by patterning the written photoresist 14.

4 is a conceptual diagram in which heterogeneous nanowires are grown by introducing a new hydrothermal synthesis step onto a first grown nanowire.

FIG. 5 is a conceptual diagram in which a heterostructure nanowire grown after removing the patterned photoresist 15 or other template from the substrate remains.

<Description of the code | symbol about the principal part of FIG. 1>

6: silicon substrate

7: Seed layer of Nanowire

8: photoresist

9: patterned photoresist

10: first grown nanowire

11: secondary growth of nanowires

Claims (2)

A method for producing a nanowire having a heterostructure in which metal oxide semiconductors, semiconductors such as silicon and germanium, or nanowire-producible materials such as carbon nanotubes are sequentially synthesized and laminated using heterogeneous materials using a photoresist pattern. The method of manufacturing a nanowire having a heterogeneous doping structure prepared by sequentially adding heterogeneous doping materials in the stacking step of heterogeneous nanowires in claim 1.

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