Substrate having optical waveguide formed therein and device comprising same

Abstract

The present invention relates to a substrate including patterned optical waveguides, the substrate including: an optical waveguide having directivity and extending in at least one direction on the substrate; and a quantum dot layer formed on the surface of the optical waveguide, wherein the quantum dot layer is a dispersion of quantum dots in an organic medium.

Description

Substrate having optical waveguide formed thereon and device including the same

[0001] The present invention relates to a substrate having an optical waveguide formed thereon and a device including the same, and more particularly, to a substrate including an optical waveguide applicable to communication devices, biosensors, quantum computing, and security devices.

[0002] Optical waveguides are optical devices used to guide and transmit light, and are utilized in diverse fields such as communications, sensing, and optical computing. Typically, optical waveguides use specific structures and materials to restrict the light transmission path and guide it in a desired direction, thereby transmitting optical signals. Existing optical waveguide technologies primarily utilize materials such as silicon (Si), indium phosphide (InP), or silica (SiO2), and various structural designs are being applied to enhance light transmission efficiency and controllability.

[0003] However, traditional optical waveguides have the disadvantage of exhibiting optimal transmission characteristics only at specific wavelengths and being limited in their response to external electronic or optical control. Research is underway to introduce new structures or materials into optical waveguides to overcome these shortcomings.

[0004] The purpose of the present invention is to propose an optical waveguide manufactured by selecting quantum dots as a photoreceptor. A technique is proposed for constructing an optical waveguide patterned with quantum dots, thereby easily controlling the wavelength that can be collected based on the size of the quantum dots. Furthermore, a technique is proposed for generating multiple outputs, each with a different color, from a single light source.

[0005] A substrate including a patterned optical waveguide according to one embodiment of the present invention may include an optical waveguide formed on the substrate and extending in at least one direction with directionality; and a quantum dot layer formed on a surface of the optical waveguide; wherein the quantum dot layer may be a quantum dot dispersed in an organic medium.

[0006] According to one embodiment, the optical waveguide may include one or more branch points that are divided into a plurality of branches, and the branch point optical waveguides may have different light-collecting wavelength ranges.

[0007] In one embodiment, the quantum dot layers of the branched optical waveguide may have different average quantum dot sizes.

[0008] According to one embodiment, the optical waveguide may have one optical input portion and multiple optical output portions.

[0009] According to one embodiment, the optical waveguide may be formed in plurality to form an optical waveguide array.

[0010] In one embodiment, the organic medium may comprise polyvinylpyrrolidone (PVP).

[0011] According to one embodiment, the optical waveguide may further include a covering layer formed between the optical waveguide and the substrate.

[0012] In one embodiment, the covering layer may include SU8 material.

[0013] In another embodiment of the present invention, a device including a substrate on which an optical waveguide is formed and through which light passes, the device may be one of a communication device, a biosensor, a quantum computing device, and a security device, and the substrate may be the substrate of claim 1.

[0014] A method for manufacturing a substrate including a patterned optical waveguide according to another embodiment of the present invention may include the steps of forming a quantum dot layer on a substrate; and the step of patterning the quantum dot layer to form an optical waveguide.

[0015] According to one embodiment, the step of forming a masking layer may be included before the step of forming the quantum dot layer.

[0016] According to one embodiment, the step of forming the optical waveguide may further include the step of forming an optical waveguide array by arranging a plurality of the optical waveguides.

[0017] According to one embodiment, the substrate may be a substrate according to one embodiment of the present invention described above.

[0018] The substrate on which the optical waveguide proposed in the present invention is patterned and the device to which the substrate is applied can convert light of any wavelength that is injected into light of a different wavelength.

[0019] Additionally, it can output light of various wavelengths without the help of a separate external wavelength splitter.

[0020] However, the effects of the present invention are not limited to the effects described above, and include all effects naturally implemented due to the various configurations proposed in the present invention.

[0021] FIG. 1 is a flowchart of a method for manufacturing a substrate including a patterned optical waveguide according to one embodiment of the present invention.

[0022] FIG. 2 is a flowchart of a method for manufacturing a device including a substrate on which an optical waveguide is formed according to one embodiment of the present invention.

[0023] FIG. 3 is a schematic diagram of a device including a substrate on which an optical waveguide is formed according to one embodiment of the present invention.

[0024] FIG. 4 is a schematic diagram showing wavelength conversion through a device according to one embodiment of the present invention.

[0025] FIG. 5 is a schematic diagram for an experiment of a device manufactured by controlling the size of quantum dots according to one embodiment of the present invention.

[0026] FIG. 6 is a graph showing changes in photocurrent, leakage current, and turn-on voltage of a device according to one embodiment of the present invention.

[0027]

[0028] The embodiments of the present invention are provided for the purpose of illustrating the technical concept of the present invention. The scope of the rights of the present invention is not limited to the embodiments presented below or the specific descriptions of these embodiments.

[0029] All technical and scientific terms used in this invention, unless otherwise defined, have the meanings commonly understood by those skilled in the art to which this invention pertains. All terms used in this invention have been selected for the purpose of more clearly explaining the invention and are not intended to limit the scope of the rights provided for in this invention.

[0030] Expressions such as “comprising,” “having,” and the like used in the present invention should be understood as open-ended terms that imply the possibility of including other embodiments, unless otherwise stated in the phrase or sentence in which the expression is included.

[0031] The singular expressions described in the present invention may include plural meanings unless otherwise stated, and this also applies to the singular expressions described in the claims.

[0032]

[0033] Hereinafter, a substrate including a patterned optical waveguide and a device including the substrate will be described in detail with reference to FIGS. 1 to 5.

[0034]

[0035] FIG. 1 is a diagram showing a substrate including a patterned optical waveguide according to one embodiment of the present invention and a method for manufacturing the substrate.

[0036] A substrate including a patterned optical waveguide according to one embodiment of the present invention may include an optical waveguide formed on the substrate and extending in at least one direction with directionality; and a quantum dot layer formed on a surface of the optical waveguide; wherein the quantum dot layer may be formed by an organic medium in which quantum dots are dispersed.

[0037] At this time, the quantum dot included in the quantum dot layer may be any one of a II-VI group semiconductor quantum dot (cadmium selenide (CdSe), cadmium sulfide (CdS), cadmium telluride (CdTe), zinc sulfide (ZnS), zinc selenide (ZnSe)), a III-V group semiconductor quantum dot (indium phosphide (InP), gallium arsenide (GaAs), gallium nitride (GaN)), a IV-VI group semiconductor quantum dot (lead sulfide (PbS), lead selenide (PbSe)), a carbon quantum dot, a silicon quantum dot, or a quantum dot of another material.

[0038] The above waveguide may include one or more branch points that divide into multiple branches, and the branched optical waveguides may have different light-collecting wavelength ranges. A light source or other form of energy may be input through the branch points. The branch points may be connected to an optical input unit so that light of an arbitrary wavelength band may be input from the light source.

[0039] According to one embodiment, the branched optical waveguide may have different wavelength ranges because the quantum dot layer is formed by quantum dots having different sizes. For example, when the quantum dot layer is formed by cadmium selenide quantum dots to emit red (R), green (G), and blue (B) light, the quantum dot sizes may be 4 to 6 nm, 2.5 to 3 nm, and 2 nm or less, respectively. The size of the quantum dot may vary depending on the material of the quantum dot. In addition, the colors output from the optical waveguide according to the present invention are not limited to R, G, and B.

[0040] According to one embodiment, the optical waveguide may have one optical input portion and multiple optical output portions. When light of an arbitrary wavelength is input to one optical input portion, light of different wavelengths may be output through the optical output portions according to the wavelength characteristics of the quantum dot layer formed on each optical waveguide.

[0041] According to one embodiment, the optical waveguides may be formed in plurality to form an optical waveguide array. The optical waveguide array may be formed in plurality on a substrate.

[0042] In one embodiment, the organic medium may include polyvinylpyrrolidone (PVP). In addition to polyvinylpyrrolidone, the organic medium may be one of polyvinyl alcohol (PVA), polyethylene glycol (PEG), hydroxypropyl methylcellulose (HPMC), and carboxymethyl cellulose (CMC).

[0043] In one embodiment, a covering layer may be further included between the optical waveguide and the substrate. Furthermore, in one embodiment, the covering layer may include SU8 material. The introduction of SU8 can ensure the stability of the device.

[0044]

[0045] A method for manufacturing a substrate including a patterned optical waveguide according to one embodiment of the present invention may include the steps of forming a quantum dot layer on a substrate; and the step of patterning the quantum dot layer to form an optical waveguide. The step of forming a housing may further be included after the step of forming the optical waveguide.

[0046] According to one embodiment, the step of forming a masking layer may be further included before the step of forming the quantum dot layer.

[0047] According to one embodiment, the step of forming the optical waveguide may further include the step of forming an optical waveguide array by arranging a plurality of the optical waveguides.

[0048] One embodiment is described with reference to Fig. 1. An optical waveguide can be formed on a glass substrate. A masking layer for optical waveguide patterning can be formed on the glass substrate. At this time, the masking layer can be formed using polyimide tape.

[0049] After a mixed solution of an organic solvent and quantum dots is spin-coated on a substrate having the above masking layer formed thereon, the masking layer is lifted off, thereby allowing the patterned optical waveguide to be retained. According to another embodiment of the present invention, a simple printing method or a spray coating method, etc., can be used. In this embodiment, quantum dots capable of focusing light (R) in the red region were used.

[0050] After the optical waveguide formation step, when light is input to the substrate, a housing can be formed to prevent the input light from being transmitted onto the substrate other than where the optical waveguide is formed. In this embodiment, the housing was formed on the substrate using insulating tape.

[0051] As a result of inputting a UV laser to a substrate including a patterned optical waveguide manufactured in the above example, it was confirmed that light of a red wavelength was output.

[0052]

[0053] FIG. 2 is a schematic diagram of the structure of a device according to one embodiment of the present invention and the manufacturing steps thereof. A method for manufacturing a device including a substrate on which an optical waveguide is formed, as one embodiment, is described in detail with reference to FIG. 2.

[0054] In a device including a substrate through which light passes through an optical waveguide, the device is one of a communication device, a biosensor, and a quantum computing security device, and the substrate may be a substrate including an optical waveguide patterned according to the present invention.

[0055] In this embodiment, an optical waveguide was formed on an indium gallium zinc oxide thin-film transistor (IGZO TFT), which is an oxide semiconductor. The IGZO TFT is formed mainly by a substrate, an insulating layer, a semiconductor channel layer, a source electrode, and a drain electrode. The substrate is a P-type heavily doped silicon substrate (P++ Si substrate), and the insulating layer is silicon oxide (SiO2) formed by a plasma chemical vapor deposition process and has a thickness of 200 nm. The semiconductor channel layer is formed of IGZO, and the source electrode and drain electrode are formed of 60 nm of titanium (Ti) and 10 nm of chromium (Cr).

[0056] Next, a covering layer can be formed on the IGZO TFT. The covering layer can be formed on the source electrode, the drain electrode, and the semiconductor channel. In the present embodiment, the covering layer is formed of SU8 material.

[0057] After forming the above-mentioned coating layer, a quantum dot dispersion containing an organic solvent and quantum dots dispersed therein is applied onto the coating layer, and then a quantum dot layer of uniform thickness can be formed by spin coating. In this example, quantum dots in the green wavelength region (G) emitting a wavelength of 550 nm were used.

[0058] As a result of inputting a UV laser to a device including a substrate on which an optical waveguide manufactured in the above example was formed, it was confirmed that light of a green wavelength was output.

[0059] In another embodiment, a neuromorphic device including the optical waveguide of the present invention can be manufactured. The neuromorphic device can include an input neuron unit, an output neuron unit, a weight control unit, a synapse array, and the optical waveguide according to the above embodiment.

[0060]

[0061] FIG. 3 is a schematic diagram of a device including a substrate on which an optical waveguide is formed according to an embodiment of the present invention. According to the schematic diagram, when a single light (e.g., a UV laser) is applied to the optical input portion of the substrate, it can be confirmed that light of different colors is output through the optical output portion. The optical waveguide of the present invention forms a quantum dot layer using a mixed solution of an organic medium and quantum dots, and at this time, the wavelength that can be collected can be easily controlled according to the size of the quantum dots. The optical waveguide and the substrate including the optical waveguide according to an embodiment of the present invention can control the wavelength without a separate external device for wavelength division because the wavelength is controlled by the size of the quantum dots in the optical waveguide. In contrast to the conventional method where only light of a desired wavelength could be transmitted, the present invention has the advantage of being able to convert light energy of a different wavelength band.

[0062]

[0063] Figure 4 is a schematic diagram illustrating wavelength conversion using a device according to one embodiment of the present invention. In this embodiment, a laser having a wavelength of 465 nm was used to input light into the device. Through this embodiment, it can be confirmed that light in the UV band applied through an optical waveguide is transmitted to a semiconductor channel layer with light energy of a wavelength of 550 nm, thereby securing a photocurrent.

[0064]

[0065] Figure 5 shows the results of applying the optical waveguide forming method of the present invention according to the wavelength of the quantum dot.

[0066] The upper picture of Fig. 5 is an optical waveguide before laser input, and the lower picture is an optical waveguide after laser input. Fig. 5(a) is an optical waveguide formed with a quantum dot layer using an organic medium and quantum dots having a wavelength that outputs the color R, Fig. 5(b) is an optical waveguide formed with a quantum dot layer using an organic medium and quantum dots having a wavelength that outputs the color G, and Fig. 5(c) is an optical waveguide formed with a quantum dot layer using an organic medium and quantum dots having a wavelength that outputs the color B.

[0067]

[0068] The graph in Fig. 6 is a graph showing the photocurrent measurement results of a device including a substrate on which the optical waveguide of Fig. 4 is formed, respectively. The photocurrent of a TFT formed with an optical waveguide based on R, G, and B quantum dots was measured, and the change in leakage current and turn-on voltage at a negative voltage before and after laser input were measured, which can be confirmed in the graph in Fig. 6.

[0069] Figure 6(a) is a graph showing the photocurrent measured after forming an optical waveguide based on R quantum dots. The red graph confirms that photocurrent was generated by UV laser input. The blue graph in Figure 6(a) shows that the threshold voltage shifted in the negative direction compared to the initial transfer curve after the laser was turned off. The green graph confirms that the threshold voltage recovered after applying a bias of Vg = 0 V, Vd = -10 V for 15 seconds to remove electrons trapped in the IGZO channel.

[0070] Fig. 6(b) is a graph showing the change in photocurrent after forming an optical waveguide based on G quantum dots, and Fig. 6(c) is a graph showing the change in photocurrent after forming an optical waveguide based on B quantum dots. Through both the graphs of Fig. 6(b) and Fig. 6(c), it can be confirmed that, as in Fig. 6(a), photocurrent was generated by the input of a UV laser and that the threshold voltage shifted in the negative direction after the laser was turned off. Through the three graphs of Figs. 6(a) to (c), it can be confirmed that the optical waveguides based on R quantum dots, G quantum dots, and B quantum dots, which are embodiments of the present invention, all have photoresponsiveness.

[0071]

[0072] The present invention proposes a technology that improves light transmission efficiency and controllability by applying quantum dots to existing optical waveguides. One embodiment of the present invention offers the advantage of controlling light absorption and emission wavelengths without additional external devices. Since the wavelength can be easily adjusted depending on the size and material composition of the quantum dots, it is expected to enable stable light transmission across a wider wavelength range.

[0073]

[0074] The above description is merely an illustrative example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. An optical waveguide formed on a substrate and extending in at least one direction with directionality; and A quantum dot layer formed on the surface of the optical waveguide; The above quantum dot layer is a quantum dot dispersed in an organic medium. A substrate comprising a patterned optical waveguide.

2. In paragraph 1, The above optical waveguide comprises one or more branch points that are divided into multiple branches, The above-mentioned branched optical waveguides have different light-collecting wavelength ranges. A substrate comprising a patterned optical waveguide.

3. In paragraph 1, The quantum dot layers of the above-mentioned branched optical waveguide have different average quantum dot sizes. A substrate comprising a patterned optical waveguide.

4. In paragraph 1, The above optical waveguide has one optical input section and multiple optical output sections. A substrate comprising a patterned optical waveguide.

5. In paragraph 1, The above optical waveguides are formed in multiple numbers to form an optical waveguide array. A substrate comprising a patterned optical waveguide.

6. In paragraph 1, The above organic medium contains polyvinylpyrrolidone (PVP). A substrate comprising a patterned optical waveguide.

7. In paragraph 1, Further comprising a covering layer formed between the optical waveguide and the substrate. A substrate comprising a patterned optical waveguide.

8. In paragraph 7, The above covering layer comprises SU8 material. A substrate comprising a patterned optical waveguide.

9. In a device including a substrate through which light passes through an optical waveguide formed therein, The above device is one of a communication device, a biosensor, a quantum computing and a security device, The above substrate is the substrate of claim 1. A device comprising a substrate on which an optical waveguide is formed.

10. A step of forming a quantum dot layer on a substrate; and A step of forming an optical waveguide by patterning the quantum dot layer; including; A method for manufacturing a substrate comprising a patterned optical waveguide.

11. In paragraph 10, Comprising a step of forming a masking layer before the step of forming the quantum dot layer, A method for manufacturing a substrate comprising a patterned optical waveguide.

12. In paragraph 10, The step of forming the above optical waveguide is: Further comprising a step of forming an optical waveguide array by arranging a plurality of the optical waveguides. A method for manufacturing a substrate comprising a patterned optical waveguide.

13. In paragraph 10, The above substrate is the substrate of claim 1. A method for manufacturing a substrate comprising a patterned optical waveguide.

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