Substrate with optical waveguide formed thereon and device including same

Abstract

The present invention relates to a substrate including a patterned optical waveguide, the substrate including an optical waveguide extending in at least one direction on the substrate with directionality, and a quantum dot layer formed on the surface of the optical waveguide, the quantum dot layer being formed by dispersing quantum dots in an organic medium.

Description

[Technical Field]

[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 that can be applied to communication devices, biosensors, quantum computing, security devices, and the like. [Background technology]

[0002] Optical waveguides are optical elements used to guide and transmit light, and are used in a variety of fields, including communications, sensing, and optical computing. In general, optical waveguides transmit optical signals by restricting the transmission path of light and guiding it in the desired direction using specific structures and materials. Existing optical waveguide technologies mainly use materials such as silicon (Si), indium phosphide (InP), or silica (SiO2), and various structural designs are applied to improve light transmission efficiency and control capabilities.

[0003] However, traditional optical waveguides have drawbacks, such as only showing optimal transmission characteristics at specific wavelengths and limited response to external electronic or optical control. To overcome these drawbacks, research is underway to introduce new structures or materials into optical waveguides. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention proposes an optical waveguide fabricated using quantum dots as a photosensitive material, a technology for easily adjusting the wavelength of light that can be collected by forming an optical waveguide patterned with quantum dots according to the size of the quantum dots, and a technology for generating multiple outputs, each with a different color, from a single light source. [Means for solving the problem]

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

[0006] According to an 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-collectible wavelength ranges.

[0007] According to an embodiment, the quantum dot layers of the branched optical waveguides may have different average quantum dot sizes.

[0008] According to one embodiment, the optical waveguide may have one optical input port and a plurality of optical outputs.

[0009] According to an embodiment, a plurality of the optical waveguides may be formed to form an optical waveguide array.

[0010] According to one embodiment, the organic medium may include polyvinylpyrrolidone (PVP).

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

[0012] According to one embodiment, the coating layer may comprise SU8 material.

[0013] In another embodiment of the present invention, in 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 described in paragraph 1.

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

[0015] According to an embodiment, the method may include forming a masking layer before forming the quantum dot layer.

[0016] According to an 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. [Effects of the Invention]

[0017] Through a substrate on which an optical waveguide proposed in the present invention is patterned and a device to which said substrate is applied, it is possible to convert light of any wavelength injected into light of a different wavelength.

[0018] Also, it is possible to output light of various wavelengths without the aid of a separate external wavelength division device.

[0019] However, the effects of the present invention are not limited to the above-mentioned effects, but include all effects that are naturally realized by the various configurations proposed in the present invention. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a flowchart of a method for manufacturing a substrate including a patterned optical waveguide according to one embodiment of the present invention. [Figure 2] 1 is a flowchart of a method for manufacturing a device including a substrate on which an optical waveguide is formed according to an embodiment of the present invention. [Figure 3] 1 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; [Figure 4] 1 is a schematic diagram illustrating wavelength band conversion through a device according to an embodiment of the present invention; [Figure 5]1 is a schematic diagram for an experiment of a device manufactured by adjusting the size of quantum dots according to an embodiment of the present invention; [Figure 6] 10 is a graph showing the photocurrent, leakage current change, and turn-on voltage change of a device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The examples of the present invention are provided for the purpose of explaining the technical concept of the present invention, and the scope of the present invention is not limited to the examples presented below or the specific descriptions of these examples.

[0022] Unless otherwise defined, all technical and scientific terms used in the present invention have the meanings commonly understood by those of ordinary skill in the art to which the present invention belongs. All terms used in the present invention are selected for the purpose of more clearly describing the present invention, and are not selected to limit the scope of the present invention.

[0023] As used herein, expressions such as "including," "comprising," and "having" should be understood as open-ended terms that include the possibility of including other embodiments, unless otherwise stated in the phrase or sentence containing the expression.

[0024] The singular expressions described in the present invention can include the plural meaning unless otherwise specified, and this also applies to the singular expressions described in the claims.

[0025] A substrate including a patterned optical waveguide and a device including the substrate will be described in detail below with reference to FIGS.

[0026] FIG. 1 relates to a substrate including a patterned optical waveguide and a method for manufacturing the substrate according to one embodiment of the present invention.

[0027] A substrate including a patterned optical waveguide according to an embodiment of the present invention may include an optical waveguide formed on a substrate and extending in at least one direction with directionality; and a quantum dot layer formed on a surface of the optical waveguide; and the quantum dot layer may be formed of an organic medium in which quantum dots are dispersed.

[0028] In this case, the quantum dots included in the quantum dot layer may be any one of II-VI group semiconductor quantum dots (cadmium selenide (CdSe), cadmium sulfide (CdS), cadmium telluride (CdTe), zinc sulfide (ZnS), zinc selenide (ZnSe)), III-V group semiconductor quantum dots (indium phosphide (InP), gallium arsenide (GaAs), gallium nitride (GaN)), IV-VI group semiconductor quantum dots (lead sulfide (PbS), lead selenide (PbSe)), carbon quantum dots and silicon quantum dots, which are other materials, or quantum dots made of other materials.

[0029] The waveguide may include one or more branching points that branch into a plurality of branches, and the branched optical waveguides may have different light-collectible wavelength ranges. A light source or other form of energy may be input through the branching points. The branching points may be connected to an optical input unit, so that light of any wavelength band may be input from the light source.

[0030] In one embodiment, the branched optical waveguide has quantum dots of different sizes forming a quantum dot layer, so that the branched optical waveguide can have different wavelength ranges. For example, when the quantum dot layer is formed of cadmium selenide quantum dots and emits red (R), green (G), and blue (B) light, the quantum dots may have sizes of 4 to 6 nm, 2.5 to 3 nm, and 2 nm or less, respectively. The size of the quantum dots may vary depending on the quantum dot material. In addition, the colors output from the optical waveguide according to the present invention are not limited to R, G, and B.

[0031] According to one embodiment, the optical waveguide may include one optical input port and a plurality of optical output ports, and when light of a given wavelength is input to one of the optical input ports, light of different wavelengths may be output through the optical output ports according to the wavelength characteristics of the quantum dot layers formed in each optical waveguide.

[0032] According to an embodiment, a plurality of the optical waveguides may be formed to form an optical waveguide array. A plurality of the optical waveguide arrays may be formed on a substrate.

[0033] According to one embodiment, the organic medium may include polyvinylpyrrolidone (PVP), and the organic medium may be one of polyvinyl alcohol (PVA), polyethylene glycol (PEG), hydroxypropyl methylcellulose (HPMC), and carboxymethyl cellulose (CMC).

[0034] According to an embodiment, a covering layer may be further included between the optical waveguide and the substrate. Also, according to an embodiment, the covering layer may include SU8 material. The introduction of SU8 may ensure stability of the device.

[0035] A method for manufacturing a substrate including a patterned optical waveguide according to an embodiment of the present invention may include forming a quantum dot layer on a substrate; and patterning the quantum dot layer to form an optical waveguide. After forming the optical waveguide, the method may further include forming a housing.

[0036] According to an embodiment, the method may further include forming a masking layer before forming the quantum dot layer.

[0037] According to an 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.

[0038] An embodiment will be described with reference to Figure 1. An optical waveguide can be formed on a glass substrate. A masking layer for patterning the optical waveguide can be formed on the glass substrate. In this case, the masking layer can be formed of polyimide tape.

[0039] A mixed solution of organic solvent and quantum dots is spin-coated on the substrate on which the masking layer is formed, and then the masking layer is lifted off to obtain a patterned optical waveguide. According to another embodiment of the present invention, a simple printing method or a spray coating method may be used. In this embodiment, quantum dots capable of condensing light in the red region (R) are used.

[0040] After the optical waveguide formation step, a housing can be formed to prevent the input light from being guided to areas of the substrate other than where the optical waveguide is formed. In this embodiment, the housing is formed on the substrate using insulating tape.

[0041] When a UV laser was applied to the substrate including the patterned optical waveguide manufactured in the above example, it was confirmed that light of a red wavelength was output.

[0042] 2 is a schematic diagram of the structure and manufacturing steps of a device according to one embodiment of the present invention. A method for manufacturing a device including a substrate on which an optical waveguide is formed, which is one embodiment of the present invention, will be described in detail with reference to FIG.

[0043] In a device including a substrate through which light passes through an optical waveguide, the device may be one of a communication device, a biosensor, and a quantum computing security device, and the substrate may include an optical waveguide patterned according to the present invention.

[0044] In this example, an optical waveguide was formed on an indium gallium zinc oxide thin-film transistor (IGZO TFT), an oxide semiconductor. The IGZO TFT is primarily composed of a substrate, an insulating layer, a semiconductor channel layer, and source and drain electrodes. The substrate is a heavily P-type doped silicon substrate (P++ Si substrate), and the insulating layer is silicon oxide (SiO2) formed by plasma enhanced chemical vapor deposition (PECVD) to a thickness of 200 nm. The semiconductor channel layer is made of IGZO, and the source and drain electrodes are made of 60 nm of titanium (Ti) and 10 nm of chromium (Cr).

[0045] 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 this example, the covering layer is made of SU8 material.

[0046] After forming the coating layer, a quantum dot dispersion containing quantum dots dispersed in an organic solvent is applied onto the coating layer, and then a quantum dot layer of uniform thickness is formed by spin coating. In this example, quantum dots in the green wavelength region (G) emitting at a wavelength of 550 nm are used.

[0047] When a UV laser was applied to a device including a substrate on which the optical waveguide manufactured in accordance with the embodiment was formed, it was confirmed that light of a green wavelength was output.

[0048] As yet another embodiment, a neuromorphic device including the optical waveguide of the present invention can be manufactured. The neuromorphic device can include an input neuron section, an output neuron section, a weight control unit, a synapse array, and the optical waveguide according to the embodiment.

[0049] FIG. 3 is a schematic diagram of a device including a substrate on which an optical waveguide according to an embodiment of the present invention is formed. From the schematic diagram, it can be seen that when one light (e.g., a UV laser) is applied to the optical input port of the substrate, different colors of light are output through the optical output port. The optical waveguide according to the present invention has a quantum dot layer formed from a mixed solution of an organic medium and quantum dots, and the wavelength that can be collected can be easily adjusted by the size of the quantum dots. The optical waveguide and substrate including the optical waveguide according to an embodiment of the present invention adjust the wavelength by adjusting the size of the quantum dots in the optical waveguide, thereby enabling wavelength adjustment without the need for an external device for wavelength division. Unlike conventional devices that only transmit light of the desired wavelength, an embodiment of the present invention has the advantage of being able to convert light energy into different wavelength bands.

[0050] 4 is a schematic diagram illustrating wavelength band conversion using a device according to an embodiment of the present invention. In this example, light was input to the device using a laser with a wavelength of 465 nm. In this example, it was confirmed that UV light applied through the optical waveguide was converted to 550 nm wavelength light energy and transferred to the semiconductor channel layer, thereby generating photocurrent.

[0051] FIG. 5 shows the results of applying the method for forming an optical waveguide of the present invention to the wavelength of quantum dots.

[0052] The upper diagram in Figure 5 shows the optical waveguide before laser input, and the lower diagram shows the optical waveguide after laser input. Figure 5(a) shows an optical waveguide with an organic medium and a quantum dot layer formed with quantum dots having a wavelength that outputs red hue, Figure 5(b) shows an optical waveguide with an organic medium and a quantum dot layer formed with quantum dots having a wavelength that outputs green hue, and Figure 5(c) shows an optical waveguide with an organic medium and a quantum dot layer formed with quantum dots having a wavelength that outputs blue hue.

[0053] The graph in Figure 6 shows the photocurrent measurement results for devices including substrates with the optical waveguides in Figure 4. The photocurrent of TFTs with R, G, and B quantum dot-based optical waveguides was measured, and the change in leakage current and turn-on voltage at negative voltage was measured before and after laser input, which can be seen in the graph in Figure 6.

[0054] Figure 6(a) is a graph showing the photocurrent measured after forming an optical waveguide based on R quantum dots. The red graph shows 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 shows that the threshold voltage recovered after applying a bias of Vg=0V, Vd=-10V for 15 seconds to remove electrons trapped in the IGZO channel.

[0055] Figure 6(b) is a graph showing the change in photocurrent after forming an optical waveguide based on G quantum dots, and Figure 6(c) is a graph showing the change in photocurrent after forming an optical waveguide based on B quantum dots. From both Figures 6(b) and 6(c), it can be seen that, as in Figure 6(a), photocurrent is generated by UV laser input, and the threshold voltage shifts in the negative direction after the laser is turned off. From the three graphs in Figures 6(a) to (c), it can be seen that the optical waveguides based on R quantum dots, G quantum dots, and B quantum dots, which are embodiments of the present invention, are all photoresponsive.

[0056] The present invention proposes a technology for improving optical transmission efficiency and controllability by applying quantum dots to existing optical waveguides. One embodiment of the present invention has the advantage of being able to adjust the optical absorption and emission wavelengths without an additional external device. Because the wavelength can be easily adjusted depending on the size and material composition of the quantum dots, it is expected that stable optical transmission will be possible over a wider wavelength band.

[0057] The above description is merely illustrative of the technical concept of the present invention, and various modifications and variations may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed herein are for illustrative purposes only and are not intended to limit the technical concept of the present invention. The scope of the present invention should be interpreted by the following claims, and all technical concepts within the scope equivalent thereto should be interpreted as being within the scope of the present invention.

Claims

1. an optical waveguide formed on a substrate and extending in at least one direction; a quantum dot layer formed on the surface of the optical waveguide; A substrate including a patterned optical waveguide, wherein the quantum dot layer is formed by dispersing quantum dots in an organic medium.

2. the optical waveguide includes one or more branch points that branch into a plurality of branches; 2. The substrate including a patterned optical waveguide according to claim 1, wherein the branched optical waveguides have different focusable wavelength ranges.

3. The substrate including a patterned optical waveguide according to claim 1 , wherein the quantum dot layers of the branched optical waveguides have different average quantum dot sizes.

4. 10. The substrate containing a patterned optical waveguide of claim 1, wherein the optical waveguide has one optical input portion and a plurality of optical outputs.

5. 2. The substrate including a patterned optical waveguide according to claim 1, wherein a plurality of said optical waveguides are formed to form an optical waveguide array.

6. 2. The substrate containing a patterned optical waveguide of claim 1, wherein the organic medium comprises polyvinylpyrrolidone (PVP).

7. The substrate containing a patterned optical waveguide of claim 1 further comprising a cover layer formed between the optical waveguide and the substrate.

8. 8. The substrate containing a patterned optical waveguide of claim 7, wherein the cover layer comprises SU8 material.

9. A device including a substrate through which light passes and through which an optical waveguide is formed, the device is one of a communications device, a biosensor, a quantum computing device, and a security device; A device including a substrate having an optical waveguide formed thereon, wherein the substrate is the substrate according to claim 1 .

10. forming a quantum dot layer on a substrate; and patterning the quantum dot layer to form an optical waveguide.

11. The method for manufacturing a substrate including a patterned optical waveguide according to claim 10 , further comprising forming a masking layer before forming the quantum dot layer.

12. The step of forming the optical waveguide includes: The method for manufacturing a substrate including a patterned optical waveguide according to claim 10, further comprising the step of arranging a number of the optical waveguides to form an optical waveguide array.

13. The method for manufacturing a substrate including a patterned optical waveguide according to claim 10, wherein the substrate is the substrate according to claim 1.

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