Method for realizing growth of PdSe2 quantum dots by magnetron sputtering and double-temperature-zone tube furnace

Abstract

The application provides a method for growing PdSe2 quantum dots by using magnetron sputtering and a double-temperature-zone tube furnace, and comprises the following steps: 1) preparing a Pd film; and 2) growing the PdSe2 quantum dots by using the Pd film and the double-temperature-zone tube furnace. The application grows the PdSe2 with a quantum dot structure by using common equipment and a conventional simple method.

Description

Technical Field

[0001] This invention relates to a method for growing PdSe2 quantum dots. Background Technology

[0002] Two-dimensional (2D) layered materials are a new type of material with unique atomic structure and excellent optoelectronic properties, providing new ideas for the preparation of high-performance optoelectronic devices. Graphene is the earliest discovered two-dimensional material, which can achieve broadband absorption from ultraviolet to far-infrared ([1] Novoselov, K. Set al. Electric field effect in atomically thincarbon films. Science 306, 666–669 (2004). However, the low light absorption of single-layer or multi-layer graphene limits its responsivity in photodetectors. In recent years, researchers have turned their attention to transition metal sulfides (TMDs) with wide bandgap variations and excellent chemical stability. However, the absorption spectra of most transition metal sulfides, such as MoS2 and SnSe2, are limited to visible light ([2] Zhuo, R.;Zeng, L.;Yuan, H.;Wu, D.;Wang, Y.;Shi, Z.;Xu, T.;Tian, ​​Y.;Li, X.;Tsang, YHIn-Situ Fabrication of PtSe2 / GaN Heterojunction for Self-Powered Deep Ultraviolet Photodetector with Ultrahigh Current On / Off Ratio and Detectivity.Nano Res.2019,12,183-189.). Fortunately, palladium diselenide (PdSe2), a transition metal sulfide based on precious metals ([3]ADOyedele,S.Yang,L.Liang,AAPuretzky,K.Wang,J.Zhang,P.Yu,PRPudasaini,AWGhosh,Z.Liu,CMRouleau,BGSumpter,MFChisholm,W.Zhou,PDRack,DBGeohegan,K.Xiao,J.Am.Chem.Soc.2017,139,14090.), not only has excellent air stability, but also a mobility as high as 40000 cm⁻¹. -2 V -1 s -1PdSe2 has a band gap an order of magnitude higher than that of black phosphorus (BP), and its band gap can vary from 1.3 eV for monolayer to 0 eV for bulk. This unique property has led to its extensive research in broadband photodetectors. Moreover, studies have shown that PdSe2 can not only extend the absorption edge of devices to the near-infrared, but also extend the light absorption to the mid-infrared, providing insights for the development of silicon-based broadband infrared detectors. However, PdSe2 prepared by CVD still suffers from thin films and insufficient light absorption ([4] Zeng, L.-H.;Wu, D.;Lin, S.-H.;Xie, C.;Yuan, H.-Y.;Lu, W.;Lau, SP;Chai, Y.;Luo, L.-B.;Li, Z.-J.;Tsang, YHControlledSynthesis of 2D Palladium Diselenide for Sensitive Photodetector Applications.Adv.Funct.Mater.2019,29,1806878.), which greatly limits its application in high-response broadband infrared photodetectors.

[0003] In recent years, in order to improve the light absorption of two-dimensional material devices, some researchers have combined quantum dots with two-dimensional materials. The larger specific surface area of ​​three-dimensional quantum dots can effectively improve the light absorption of the device, thereby improving the responsivity of the device. Secondly, two-dimensional materials have high carrier mobility, and quantum dots can be used as a transport channel to avoid the carrier mobility being too low. Furthermore, the three-dimensional quantum effect of quantum dots can effectively improve the quantum efficiency of the device, and the discrete energy levels in quantum dots can also improve the broad spectrum absorption of the device, compensating for the limited response spectrum of two-dimensional materials ([5] Kufer, D.; Nikitskiy, I.; Lasanta, T.; Navickaite, G.; Koppens, FH; Konstantatos, G. Hybrid 2D-0D MoS2-PbS quantumdot photodetectors. Adv. Mater. 2015, 27, 176–180.).

[0004] However, the current methods for combining quantum dots with two-dimensional materials are generally to transfer quantum dots onto two-dimensional materials through solution spin coating or to transfer two-dimensional materials onto three-dimensional quantum dot structures through thin film transfer ([6] Karnatak, P.; Paul, T.; Islam, S.; Ghosh, A. 1 / f noise in van der Waals materials and hybrids. Adv. Phys.-X 2017, 2, 428–449.). However, these methods are not only cumbersome to operate but also have a large degree of uncontrollability, which is not conducive to large-scale production. Secondly, the materials of two-dimensional materials and quantum dots are generally inconsistent. The heterogeneous integration interface often produces Fermi pinning effect due to interface states, potential barriers and other problems, which greatly restricts the transport of charge carriers at the interface. Therefore, the key to solving the above problems is to prepare PdSe2 quantum dots in one step. Summary of the Invention

[0005] This invention provides a method for growing PdSe2 quantum dots using magnetron sputtering and a dual-temperature zone tube furnace. The purpose is to overcome the shortcomings of existing technologies and grow PdSe2 with quantum dot structures using common equipment and conventional, simple methods.

[0006] The technical solution of this invention is as follows:

[0007] 1) The preparation of Pd thin films is carried out using the following specific methods:

[0008] (1) The SiO2 wafer was ultrasonically cleaned for 10 min in sequence with acetone, anhydrous ethanol, and deionized water to remove organic matter from the surface; after treatment, the SiO2 wafer was spin-dried and placed into a high vacuum thin film deposition system, and the vacuum degree of the sputtering chamber was evacuated to 1×10⁻⁶. -4 Pa.

[0009] (2) After the process in step (1), adjust the temperature control system to heat up the sample tray.

[0010] (3) After the treatment in step (2), wait for the temperature to stabilize and the vacuum degree to be less than 1×10. -4 Pa, introduce Ar gas with a purity of 5N into the sputtering chamber and maintain it for 10-15 minutes. Then, adjust the vacuum rate to make the chamber pressure 0.5-0.8 Pa and maintain it for 5-10 minutes.

[0011] (4) After the processing in step (3), the sputtering rate of Pd film is adjusted by setting the DC sputtering power supply power and the rotation speed of the sample tray, and a Pd film with a thickness of 7nm-10nm is sputtered on the SiO2 wafer.

[0012] (5) By controlling the heat preservation time, the density of the Pd film is enhanced.

[0013] Further: In step 1) part (2), the sample tray is heated, and the temperature is controlled at 300℃-600℃.

[0014] Further: In step 1) in part (4), the DC sputtering power supply power and rotation speed are set to 20-100W and 5-10rpm / min, respectively.

[0015] Further: In step 1) in part (5), the heat preservation time is controlled by a temperature control system. The heat preservation time is input as 10-30 minutes, and the temperature is automatically reduced after the time is reached.

[0016] Further: in step 1), parts (4) and (5) involve low-power sputtering followed by heat preservation for 10-30 minutes to enhance the density of the film and to initially form an island-like structure with a three-dimensional morphology.

[0017] 2) PdSe2 quantum dot growth was achieved using magnetron sputtering of Pd thin films and a dual-temperature zone tube furnace. The specific method is as follows:

[0018] (1) Place the SiO2 sheet with Pd growth on a quartz plate and send it into a dual-temperature zone tube furnace, placing it in the lower temperature zone.

[0019] (2) Sprinkle the Se powder into another quartz plate, place it in the upper temperature zone of the dual-temperature zone tube furnace, and seal the tube furnace.

[0020] (3) The dual-temperature zone tubular furnace is purged three times. First, the vacuum degree of the tubular furnace is evacuated to 1×10 using a mechanical pump. -1 Pa. Then switch the flow meter to the cleaning setting, open the air inlet valve to introduce Ar gas, and wait for the vacuum in the tubular furnace chamber to rise back to 0 Pa. Then repeat the above operation twice.

[0021] (4) Open the gas outlet valve of the tubular furnace and ventilate in cleaning mode.

[0022] (5) Switch the flow meter in step (4) to valve control mode and set the ventilation flow rate.

[0023] (6) After the switching in step (5) is completed, set the heating rate and cut-off temperature of the upper and lower temperature zones, and set the heat preservation time.

[0024] (7) Once the heat preservation time in step (6) is over, the growth of PdSe2 quantum dots is achieved.

[0025] Further: In step 2), part (1) involves elevating the film by 5 cm and placing it inside a quartz tube with a diameter of 9 cm, so that the film is directly below the tube furnace temperature sensor. The spacing between the Pd-grown SiO2 and Se powder is 22 cm.

[0026] Further: in step 2), part (2) contains 1g-3g of Se powder.

[0027] Further: In step 2) part (4), the ventilation time should be 2-3 minutes to flush the air in the outlet pipe.

[0028] Further: In step 2) in part (5), the Ar gas flow rate is 100 sccm.

[0029] Further: In step 2) part (6), the heating rate of the lower temperature zone is set to 10℃ / min, heating to 450℃, the lower temperature zone heating rate is 10℃ / min, heating to 450℃, and the Se oxidation time is 5h. The Ar gas flow rate during the Se oxidation process is 100sccm.

[0030] The beneficial effects of this invention are as follows:

[0031] This invention provides a method for growing PdSe2 quantum dots using magnetron sputtering and a dual-temperature zone tube furnace. This method not only avoids the cumbersome substrate preparation process but also eliminates uncontrollable variables introduced by operational complexity. This invention utilizes magnetron sputtering and a dual-temperature zone tube furnace to prepare PdSe2 quantum dots, a simple and low-cost material preparation method. Attached Figure Description

[0032] Figure 1 This is a graph showing the AFM detection results of the samples obtained in an embodiment of the present invention;

[0033] Figure 2 This is a graph showing the AFM detection results of the samples obtained in an embodiment of the present invention;

[0034] Figure 3 This is a diagram showing the Raman test results of the samples obtained in an embodiment of the present invention;

[0035] Figure 4 The image shows the XRD test results of the sample obtained in the embodiment of the present invention. Detailed Implementation

[0036] The following embodiments will further illustrate the present invention with reference to the accompanying drawings.

[0037] The equipment used was a CK-450 high-vacuum magnetron sputtering thin film deposition system, which has two DC target positions and one RF target position in the vacuum chamber. The target material used was a 5N (99.999%) Ge circular target, and the SiO2 wafer used was a 100nm thick wafer grown on a Si wafer.

[0038] 1. The specific methods for processing SiO2 substrate materials are as follows:

[0039] 1) Select a 100nm thick SiO2 substrate material and clean it with acetone and anhydrous ethanol to remove organic matter from the surface of the SiO2 substrate; after cleaning, spin-dry the SiO2 wafer using a spin coater and place it into a high vacuum thin film deposition system, waiting for the vacuum level in the chamber to reach 1×10⁻⁶. -4 Pa;

[0040] 2) Adjust the temperature control system to heat the sample tray;

[0041] 3) After the temperature stabilizes at the set value, introduce high-purity Ar gas into the cavity and maintain it for 10 minutes. Adjust the vacuuming rate to stabilize the pressure at 0.5-0.8 Pa and maintain it for 5 minutes. Then turn on the sputtering power supply.

[0042] 4) Set the DC sputtering power supply to 20W, the sample tray rotation speed to 10rpm / min, and sputter for 90s to leave a 7-10nm thick Pd layer on the SiO2 substrate.

[0043] 5) Set the vacuum pumping rate to maximum and keep the sample tray warm for 10-30 minutes to improve the density of the Pd film.

[0044] 2. The PdSe2 quantum dots were grown using a dual-temperature zone tube furnace. The specific method is as follows:

[0045] 1) Place the SiO2 sheet with Pd growth on a quartz plate and send it into a dual-temperature zone tube furnace, placing it in the lower temperature zone to ensure that the SiO2 is in the center of the temperature sensor.

[0046] 2) Sprinkle the Se powder into another quartz plate, place it in the upper temperature zone of the dual-temperature zone tube furnace, and ensure that the tube furnace is sealed in the center zone of the temperature sensor.

[0047] 3) The dual-temperature zone tubular furnace is purged three times. First, a mechanical pump is used to evacuate the tubular furnace to a vacuum level of 1×10⁻⁶. -1 Pa. Then switch the flow meter to the cleaning setting, open the air inlet valve to introduce Ar gas, and wait for the vacuum to rise back to 0 Pa. Repeat step 3 twice.

[0048] 4) Open the gas outlet valve of the tubular furnace and ventilate in cleaning mode for 2-3 minutes.

[0049] 5) Switch the flow meter to valve-controlled mode and set the ventilation flow rate to 100 sccm.

[0050] 6) After setting the gas flow rate, set the heating rate of the upper and lower temperature zones to 10℃ / min, raise the temperature to 450℃, and set the holding time to 5h.

[0051] 7) Once the heat preservation time in step (6) is over, the growth of PdSe2 quantum dots is achieved.

[0052] 8) Perform atomic force microscopy (AFM) on the PdSe2 quantum dot samples grown in step 7), such as... Figure 1 , Figure 2 As shown, the Se-treated sample exhibits an uneven surface. The figure shows a roughness (RMS) of 6.264 nm, indicating that the sample surface has a quantum dot morphology.

[0053] like Figure 3 As shown, the Se-treated samples show high values ​​at 144, 206, 222, and 256 cm⁻¹. -1 The presence of four distinct peaks indicates that PdSe2 was successfully prepared.

[0054] like Figure 4 As shown, the XRD test was performed on the sample after growth in step 8). It can be seen that the XRD shows two crystal phases, (002) and (122).

[0055] Matters not covered in this invention are common knowledge.

[0056] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for growing PdSe2 quantum dots by magnetron sputtering and double-temperature-zone tube furnace, characterized in that The method comprises the following steps: 1) Preparation of Pd film, the specific method is as follows: (1) After the surface of SiO2 plate is cleaned and dried, it is put into a high vacuum thin film deposition system, vacuum is extracted to make the vacuum degree of sputtering cavity reach 1×10 -4 Pa; (2) After the treatment in step (1), the sample tray is subjected to temperature control system for temperature rising treatment, and the temperature is controlled at 300-600 DEG C; (3) After step (2), wait until the temperature stabilizes at the set value and the chamber vacuum is less than 1 x 10 -4 Pa, introduce Ar gas with a purity of 5N into the sputtering chamber, and then adjust the rate of vacuum pumping so that the chamber pressure stabilizes at 0.5-0.8 Pa; (4) Pd film is sputtered by setting the power of direct current sputtering power and the rotation speed of sample tray, wherein the power is set to 20 W, and the rotation speed is set to 5-10 rpm / min; (5) The compactness of Pd film is enhanced by heat preservation, and the heat preservation time is set to 10-30 min; 2) PdSe2 quantum dot growth is realized by using Pd film and double-temperature-zone tube furnace, and the specific method is as follows: (1) The SiO2 sheet with Pd growth is placed on the quartz sheet and sent into the double-temperature-zone tube furnace, and placed in the lower temperature zone; (2) Se is scattered into another quartz sheet and placed in the upper temperature zone of the double-temperature-zone tube furnace, wherein the mass of Se powder is 1-3 g; (3) The tube furnace is washed three times, and then Se is formed by heating, and 5N Ar gas is introduced as carrier gas, that is, PdSe2 quantum dot growth is realized, wherein the Se formation condition is that the lower temperature zone and the upper temperature zone are heated to 450 DEG C at a rate of 10 DEG C / min, the heat preservation time is set to 5h, and the Ar gas flow is 100 sccm.

2. The method for growing PdSe2 quantum dots by magnetron sputtering and double-temperature-zone tube furnace according to claim 1, characterized in that: In step 1) of part (3), Ar gas is introduced at a flow rate of 15 sccm for 10-15 min, and then the gate valve is slowly rotated, the cavity pressure is maintained at 0.5-0.8 Pa for 5-10 min.

3. The method for growing PdSe2 quantum dots by magnetron sputtering and double-temperature-zone tube furnace according to claim 1, characterized in that: In step 1) of part (5), the heat preservation time is controlled by the temperature control system, and the heat preservation time is set to 10-30 min, and the temperature is automatically lowered after the time reaches.

4. The method for growing PdSe2 quantum dots by magnetron sputtering and double-temperature-zone tube furnace according to claim 1, characterized in that: In step 1) of part (5), the compactness of the film is enhanced by heat preservation for 10-30 min, and the film is preliminarily formed into an island structure with three-dimensional morphology.

5. The method for growing PdSe2 quantum dots by magnetron sputtering and double-temperature-zone tube furnace according to claim 1, characterized in that: In step 2) of part (1), the film is raised by 5 cm and placed in a quartz tube with a diameter of 9 cm, so that the film is located directly below the temperature sensor of the tube furnace, and the distance between the SiO2 with Pd growth and the Se powder is 22 cm.

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