A metal quantum dot array configuration regulation method

Abstract

The application discloses a kind of metal quantum dot array configuration regulation methods, comprising: substrate is annealed;Target material is cleaned using laser;After cleaning target material, the growth of target material quantum dot is carried out on substrate;In the growth of target material quantum dot, in-situ reflection high-energy electron diffraction device monitors target material quantum dot growth process, judges the growth mode and growth state of target material quantum dot by diffraction pattern, and the growth orientation of target material quantum dot is analyzed and judged by the change of diffraction spot or diffraction stripe in diffraction pattern.The application utilizes pulsed laser deposition method, by changing the frequency, energy density, pulse number of pulsed laser effect, realizes that solid thin film surface obtains size, shape, spacing in-situ adjustable metal quantum dot array in ultra-high vacuum.The size of prepared metal quantum dot is less than 100nm, metal quantum dot configuration element component, size, shape, spacing is easy to control, experiment repeatability is good, non-toxic, and operation safety is high.

Description

Technical Field

[0001] This invention belongs to the field of metal materials technology, and more specifically, this invention relates to a method for controlling the configuration of metal quantum dot arrays. Background Technology

[0002] Due to their small particle size (1–100 nm), quantum dots possess unique structures that result in physical properties unmatched by bulk materials, including quantum size effects, localized surface plasmon resonance, and quantum tunneling effects, thus exhibiting special magnetic, thermal, electrical, and mechanical properties. Compared to semiconductor quantum dots, metallic quantum dots possess higher electron density, larger effective mass, and shorter phase coherence length, leading to better electrical and thermal conductivity. Furthermore, metallic quantum dots exhibit better ductility than semiconductor quantum dots, making them easier to fabricate at smaller scales, thus enabling the manipulation of various quantum effects. Quantum dot fabrication methods are mainly divided into two major systems: liquid-phase preparation and solid-phase preparation. In the liquid-phase quantum dot preparation system, the most commonly used method is the organometallic method, which obtains metallic quantum dots of different configurations, including mononuclear quantum dots and core-shell quantum dots, through the pyrolysis of precursors in high-boiling-point metal-organic solvents (using methods such as high-pressure reactors and microwave heating). Liquid-phase preparation methods offer good control over the size and shape of metal quantum dots, exhibiting high fluorescence quantum yield, narrow fluorescence half-width, good monodispersity, and stability. However, the liquid-phase chemical environment makes the spacing between metal quantum dots uncontrollable, and the high experimental cost, toxicity of organic reagents, and low operational safety limit the application of this method. Another solid-phase preparation method primarily uses the sol-gel process to prepare metal quantum dots. This method involves hydrolyzing alkoxides and inorganic salts of metals, then polymerizing and gelling the solute, followed by drying and heat treatment of the gel to obtain nanoparticle films or glass. Solid-phase preparation yields products with high purity, uniform and fine particle size, low synthesis temperature, and easy process control; however, the spacing between metal quantum dots within the colloidal layer cannot be controlled. In summary, both existing liquid-phase and solid-phase metal quantum dot preparation methods require changes to the external experimental environment to control their size and shape, resulting in poor in-situ fine control over the configuration (elemental composition, size, shape, spacing, etc.) of the metal quantum dots, significantly limiting the optimization of quantum device performance. Summary of the Invention

[0003] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0004] To achieve these objectives and other advantages according to the present invention, a method for fabricating a metal quantum dot lattice on a substrate is provided, comprising the following steps:

[0005] Step 1: Anneal the substrate;

[0006] Step 2: Clean the target material using a laser;

[0007] Step 3: After cleaning the target material, grow quantum dots on the substrate.

[0008] Step 4: During the growth of quantum dots in the target material, an in-situ reflective high-energy electron diffraction device is used to monitor the growth process of the quantum dots in the target material. The growth mode and growth state of the quantum dots in the target material are determined by the diffraction pattern. The growth orientation of the quantum dots in the target material is analyzed and judged by the changes in the diffraction spots or diffraction fringes in the diffraction pattern.

[0009] Preferably, in step one, the substrate is a solid substrate or a thin film, and the solid substrate includes a single-crystal SrTiO3 substrate.

[0010] Preferably, the target material is a metal with a purity greater than 99.99%, including Fe, Co, Ni, V, Cr, Mn, FeNi, FeCo, SmCo, and FeP metal targets.

[0011] The method for controlling the configuration of a metal quantum dot lattice as described in claim 1, characterized in that, in step one, the specific method for annealing the substrate includes: firstly, placing the substrate on the sample stage in the main cavity of the pulsed laser deposition system, wherein the back vacuum level of the vacuum cavity is less than 5 × 10⁻⁶. -7 Pa, thus beginning the high-temperature annealing of the substrate; the annealing process is as follows: the temperature is increased from room temperature to 600-800℃ at a rate of 5℃ / min, then oxygen is introduced into the vacuum chamber, and the pressure of the vacuum chamber is adjusted to 5-20Pa by the oxygen flow controller. The entire annealing process lasts for 20-40 minutes, and then the annealing is ended and the substrate is allowed to cool naturally to room temperature.

[0012] Preferably, in step three, the specific method for growing metal Fe quantum dots on a single-crystal SrTiO3 substrate includes: using metal Fe as a target material, the pulsed laser of the laser is incident at 45° on the metal Fe target material in the vacuum cavity through a corner mirror, and the sputtered plasma plume is deposited on the single-crystal SrTiO3 substrate, thereby preparing a metal Fe quantum dot array on the single-crystal SrTiO3 substrate.

[0013] Preferably, the back vacuum is set to less than 5 × 10⁻⁶. -7 Pa, the working vacuum is maintained at less than 5 × 10 - 5 Pa uses a 248nm KrF excimer ultraviolet laser with a laser pulse frequency of 0–10Hz and a laser energy density of 1–10 J / cm². 2The number of laser pulses applied to the Fe metal target is 0 to 1000 pulses, the distance between the Fe metal and the single-crystal SrTiO3 substrate is 5 cm, and the morphology of the prepared metal quantum dots is spherical or conical.

[0014] Preferably, in step four, during the growth of the quantum dots on the target material, an in-situ reflective high-energy electron diffraction device monitors the growth process of the quantum dots on the target material. The incident electron beam energy of the in-situ reflective high-energy electron diffraction device is adjustable in the range of 0 to 30 keV, and it is grazing incident on the substrate surface at an angle of 1° to 5°. The high-energy electrons after interacting with the substrate are imaged on a fluorescent screen, and the diffraction pattern is monitored in real time by a CCD. The computer processes the diffraction image.

[0015] A method for controlling the configuration of a metal quantum dot array includes: obtaining a metal quantum dot array with in-situ adjustable size, shape, and spacing on the surface of a solid substrate or thin film in ultra-high vacuum by changing the laser frequency, energy density, and number of pulses.

[0016] This invention offers at least the following advantages: It uses high-purity single-element or multi-element metal targets as the main raw material for growing metal quantum dots, enabling the acquisition of metal quantum dots of different types and elemental composition ratios. During the growth process, in-situ monitoring is performed using an in-situ reflective high-energy electron diffraction device, allowing for real-time acquisition of the growth status of the metal quantum dots. Furthermore, by combining changes in the frequency, energy density, and number of pulses of the pulsed laser, the configuration (elemental composition, size, shape, and spacing) of different metal quantum dots can be precisely controlled in situ. The entire experimental process employs pulsed laser deposition in physical vapor deposition, offering high controllability, good experimental repeatability, non-toxicity, and high operational safety, making it suitable for the mass production of high-quality metal quantum dots.

[0017] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0018] Figure 1 The laser energy density in Example 4 is 2 J / cm². 2 Morphology of the prepared Fe quantum dot lattice;

[0019] Figure 2 The laser energy density in Example 5 is 6 J / cm². 2 Morphology of the prepared Fe quantum dot lattice;

[0020] Figure 3 The image shows a comparison of the fluorescence intensity of the metal Fe quantum dot arrays and single-crystal SrTiO3 substrates prepared in Examples 1-4. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0022] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0023] Example 1

[0024] This embodiment provides a method for preparing a metallic Fe quantum dot array on a single-crystal SrTiO3 substrate, including the following steps:

[0025] Step 1: Anneal the single-crystal SrTiO3 substrate. The specific method includes: first, placing the substrate on the sample stage in the main cavity of the pulsed laser deposition system; the background vacuum level of the vacuum chamber is less than 5 × 10⁻⁶. -7 Pa, thus starting the high-temperature annealing of the substrate; the annealing process is as follows: the temperature is increased from room temperature to 700℃ at a rate of 5℃ / min, then oxygen is introduced into the vacuum chamber, and the pressure of the vacuum chamber is adjusted to 10Pa by the oxygen flow controller. The entire annealing process lasts for 30 minutes, and then the annealing is ended and the substrate is allowed to cool naturally to room temperature.

[0026] Step 2: Clean the Fe metal target using a laser. The Fe metal target must be Fe metal with a purity greater than 99.99%.

[0027] Step 3: After cleaning the Fe target, grow Fe quantum dots on the substrate. Specific methods include setting the back vacuum to less than 5 × 10⁻⁶. -7 Pa, the working vacuum is maintained at less than 5 × 10 -5 Pa was achieved using a 248nm KrF excimer ultraviolet laser with a laser pulse frequency of 2Hz and a laser energy density of 2J / cm². 2 The number of laser pulses acting on the Fe target is 200, which means that the number of Fe quantum dots deposited is 200. The distance between the Fe and the single-crystal SrTiO3 substrate is 5 cm. The laser pulses are incident on the Fe target in the vacuum cavity at 45° through a rotating mirror. The sputtered plasma plume is deposited on the single-crystal SrTiO3 substrate, thus a Fe quantum dot array is prepared on the single-crystal SrTiO3 substrate.

[0028] Step 4: During the growth of Fe target quantum dots, an in-situ reflective high-energy electron diffraction device is used to monitor the growth process. The incident electron beam energy of the in-situ reflective high-energy electron diffraction device is adjustable within the range of 20keV. It is grazing incident on the substrate surface at a 5° angle. The high-energy electrons after interacting with the substrate are imaged on a fluorescent screen. The diffraction pattern is monitored in real time by a CCD. The computer processes the diffraction image and determines the growth mode and growth state of the target quantum dots through the diffraction pattern. The growth orientation of the target quantum dots is analyzed and judged by the changes in the diffraction spots or diffraction fringes in the diffraction pattern.

[0029] Example 2

[0030] This embodiment provides a method for preparing a metallic Fe quantum dot array on a single-crystal SrTiO3 substrate. The difference from Embodiment 1 is that the number of laser pulses acting on the metallic Fe target is 400, that is, the number of deposited metallic Fe quantum dots is 400. The rest of the process is the same as in Embodiment 1.

[0031] Example 3

[0032] This embodiment provides a method for preparing a metallic Fe quantum dot array on a single-crystal SrTiO3 substrate. The difference from Embodiment 1 is that the number of laser pulses acting on the metallic Fe target is 600, that is, the number of deposited metallic Fe quantum dots is 600. The rest of the process is the same as in Embodiment 1.

[0033] Example 4

[0034] This embodiment provides a method for preparing a metallic Fe quantum dot array on a single-crystal SrTiO3 substrate. The difference from Embodiment 1 is that the number of laser pulses acting on the metallic Fe target is 800, that is, the number of deposited metallic Fe quantum dots is 800. The rest of the process is the same as in Embodiment 1.

[0035] like Figure 1 As shown, the prepared metal quantum dots have a spherical morphology and a size of less than 5 nm.

[0036] The fluorescence intensity of the metal Fe quantum dot arrays and the single-crystal SrTiO3 substrates prepared in Examples 1-4 were measured respectively to obtain... Figure 3 ,from Figure 3 It can be seen that after preparing metal Fe quantum dot arrays on single-crystal SrTiO3 substrates in Examples 1-4, the fluorescence intensity is stronger than that of single-crystal SrTiO3 substrates. Among them, the sample prepared by laser pulse number 800 in Example 4 has the most significant enhancement in fluorescence intensity.

[0037] Example 5

[0038] This embodiment provides a method for preparing metallic Fe quantum dot arrays on a single-crystal SrTiO3 substrate, which differs from Embodiment 1 in that the laser energy density in step three is 6 J / cm². 2 The remaining processes are the same as in Example 1, such as... Figure 2 As shown, the prepared metal quantum dots have a cone-like morphology and a size of less than 100 nm.

[0039] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0040] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for fabricating a metal quantum dot array on a substrate, characterized in that, Includes the following steps: Step 1: Anneal the substrate; Step 2: Clean the target material using a laser; Step 3: After cleaning the target material, grow quantum dots on the substrate. Step 4: During the growth of quantum dots in the target material, an in-situ reflective high-energy electron diffraction device is used to monitor the growth process of the quantum dots in the target material. The growth mode and growth state of the quantum dots in the target material are determined by the diffraction pattern. The growth orientation of the quantum dots in the target material is analyzed and judged by the changes in the diffraction spots or diffraction fringes in the diffraction pattern. In step one, the substrate is a single-crystal SrTiO3 substrate; In step two, the target material is a metallic Fe target material with a purity greater than 99.99%. In step one, the specific method for annealing the substrate includes: first, placing the substrate on the sample stage in the main cavity of the pulsed laser deposition system, with the back vacuum level of the vacuum cavity being less than 5 × 10⁻⁶. -7 Pa, thus beginning the high-temperature annealing of the substrate; the annealing process is as follows: the temperature is raised from room temperature to 600~800℃ at a rate of 5℃ / min, then oxygen is introduced into the vacuum chamber, and the pressure of the vacuum chamber is adjusted to 5~20Pa by the oxygen flow controller. The entire annealing process lasts for 20~40min, and then the annealing is ended and the substrate is allowed to cool naturally to room temperature. In step three, the specific method for growing metal Fe quantum dots on a single-crystal SrTiO3 substrate includes: using metal Fe as a target material, the pulsed laser of the laser is incident on the metal Fe target material in the vacuum cavity at 45° through a corner mirror, and the sputtered ion plume is deposited on the single-crystal SrTiO3 substrate, thereby preparing a metal Fe quantum dot array on the single-crystal SrTiO3 substrate; Set the back vacuum to less than 5×10 -7 Pa, the working vacuum is maintained at less than 5 × 10 -5 Pa uses a 248nm KrF excimer ultraviolet laser with a laser pulse frequency of 0~10Hz and a laser energy density of 1~10J / cm². 2 The number of laser pulses applied to the Fe metal target is 0 to 1000 pulses, the distance between the Fe metal and the single crystal SrTiO3 substrate is 5 cm, and the morphology of the prepared metal quantum dots is spherical or conical. In step four, during the growth of quantum dots on the target material, an in-situ reflective high-energy electron diffraction device monitors the growth process of the quantum dots on the target material. The incident electron beam energy of the in-situ reflective high-energy electron diffraction device is adjustable in the range of 0~30keV, and it is grazing incident on the substrate surface at an angle of 1°~5°. The high-energy electrons after interacting with the substrate are imaged on a fluorescent screen, and the diffraction pattern is monitored in real time by a CCD. The computer processes the diffraction image.

Images