Regulation and control method for inhibiting intrinsic defects of two-dimensional transition metal chalcogenide
Through the annealing treatment and interface coupling technology of sapphire substrates, the problem of surface defects of two-dimensional transition metal chalcogenides is solved, the optical performance of the material is improved, and the foundation for high-brightness light-emitting diodes are laid.
Patent Information
- Application Number
- CN202411816245.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-08-29
Smart Images
Figure CN120568892A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of two-dimensional transition metal chalcogenides, and more specifically, to a method for controlling the intrinsic defects of two-dimensional transition metal chalcogenides. Background Art
[0002] Two-dimensional transition metal dichalcogenides (TMDs) have important applications in optoelectronic devices due to their unique structure and physical properties. However, due to the two-dimensional nature of TMDs, surface defects inevitably exist, significantly reducing the photoluminescence quantum efficiency, exciton lifetime, and carrier diffusion length of the material, thereby affecting the performance of light-emitting diodes and photodetectors. Exploring effective and simple methods to suppress TMD defect effects is a key scientific issue in the regulation of two-dimensional material properties and device design. Summary of the Invention
[0003] The present application provides a method for regulating the intrinsic defects of two-dimensional transition metal chalcogenides. This method can alleviate the problem that the photoluminescence quantum efficiency, exciton lifetime and carrier diffusion length of the material are reduced due to the inevitable presence of some defects on the surface of TMDs, resulting in performance degradation of light-emitting diodes, photodetectors, etc.
[0004] The embodiment of the present application is implemented as follows:
[0005] In a first aspect, the present application provides a method for suppressing intrinsic defects in two-dimensional transition metal chalcogenides, comprising:
[0006] Mechanically exfoliating a monolayer of two-dimensional transition metal chalcogenide onto the surface of an annealed substrate;
[0007] The annealing treatment includes holding the temperature at 800°C to 1300°C for 4h to 12h in an oxygen-containing atmosphere;
[0008] Among them, the two-dimensional transition metal sulfide compound is WS2, and the substrate is an a-plane sapphire substrate; or, the two-dimensional transition metal sulfide compound is WSe2, and the substrate is a c-plane sapphire substrate.
[0009] The control method provided in this application utilizes interface coupling to suppress the defect effects of monolayer TMDs, and realizes efficient intrinsic radiation recombination (photon) luminescence of excitons by selecting the composition of two-dimensional transition metal chalcogenides and the corresponding crystal plane of the sapphire substrate, laying the foundation for the application of high-brightness, narrow-spectrum light-emitting diodes based on two-dimensional materials.
[0010] In some alternative embodiments, the oxygen-containing atmosphere includes air.
[0011] In some optional embodiments, the temperature of the annealing treatment is 1000°C-1200°C.
[0012] In some optional embodiments, the temperature of the annealing treatment is 1100°C-1200°C.
[0013] In some optional embodiments, the annealing treatment time is 6 hours to 10 hours.
[0014] In a second aspect, the present application provides an example method for suppressing intrinsic defects of two-dimensional transition metal chalcogenides, which comprises:
[0015] growing a two-dimensional transition metal chalcogenide on the surface of an annealed sapphire substrate;
[0016] The annealing treatment includes maintaining the temperature at 800°C-1300°C for 4h-12h in an oxygen-containing atmosphere;
[0017] The two-dimensional transition metal chalcogenide is WS2, and the sapphire substrate is an a-plane sapphire substrate; alternatively, the two-dimensional transition metal chalcogenide is WSe2, and the surface of the sapphire substrate is a c-plane.
[0018] The control method provided in this application utilizes interface coupling to suppress the defect effects of monolayer TMDs, and realizes efficient intrinsic radiation recombination (photon) luminescence of excitons by selecting the composition of two-dimensional transition metal chalcogenides and the corresponding crystal plane of the sapphire substrate, laying the foundation for the application of high-brightness, narrow-spectrum light-emitting diodes based on two-dimensional materials.
[0019] In some alternative embodiments, the oxygen-containing atmosphere includes air.
[0020] In some optional embodiments, the number of layers of the two-dimensional transition metal chalcogenide is 1.
[0021] In some optional embodiments, the temperature of the annealing treatment is 1000°C-1200°C.
[0022] In some optional embodiments, the annealing treatment time is 6 hours to 10 hours. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.
[0024] Figure 1 Optical images of single-layer WS2 on different substrates in Example 1 and Comparative Examples 1-2;
[0025] Figure 2The photoluminescence spectra of single-layer WS2 on different substrates in Example 1 and Comparative Examples 1-2 at 7K and 298K;
[0026] Figure 3 Optical images of single-layer WSe2 on different substrates in Example 2 and Comparative Examples 4-5;
[0027] Figure 4 The photoluminescence spectra of single-layer WSe2 on different substrates in Example 2 and Comparative Examples 4-5 at 7K and 298K;
[0028] Figure 5 These are AFM images of the c-plane sapphire substrates before and after annealing treatment in Example 2 and Comparative Example 6. DETAILED DESCRIPTION
[0029] The embodiments of the present application will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.
[0030] The following is a detailed description of the method for suppressing intrinsic defects of two-dimensional transition metal chalcogenides according to the embodiment of the present application:
[0031] The present application provides a method for suppressing intrinsic defects of two-dimensional transition metal chalcogenides, which comprises:
[0032] Mechanically exfoliating a monolayer of two-dimensional transition metal chalcogenide onto the surface of an annealed substrate;
[0033] The annealing treatment includes holding the temperature at 800°C to 1300°C for 4h to 12h in an oxygen-containing atmosphere;
[0034] Among them, the two-dimensional transition metal sulfide compound is WS2, and the substrate is an a-plane sapphire substrate; or, the two-dimensional transition metal sulfide compound is WSe2, and the substrate is a c-plane sapphire substrate.
[0035] The a-plane sapphire substrate and the c-plane sapphire substrate are annealed in an oxygen atmosphere at 800°C-1300°C for 4-12 hours. This facilitates atomic diffusion and crystal structure rearrangement under the high-temperature heat treatment, resulting in a regular distribution of nanoscale steps on the sapphire substrate surface. A monolayer of two-dimensional transition metal chalcogenide is then mechanically exfoliated onto the annealed substrate surface, where interfacial coupling is utilized to suppress the defect effects of the monolayer TMDs. Furthermore, by selecting the composition of the two-dimensional transition metal chalcogenide and the corresponding crystal plane of the sapphire substrate, efficient intrinsic radiative recombination (photon luminescence) of excitons is achieved, thereby suppressing the intrinsic defects of the two-dimensional transition metal chalcogenide.
[0036] Illustratively, the temperature of the annealing treatment is any one of 800° C., 900° C., 1000° C., 1100° C., 1200° C., 1300° C., or between any two values.
[0037] Exemplarily, the annealing time is any one of 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, and 12 h, or between any two values.
[0038] That is, the control method provided in this application utilizes interface coupling to suppress the defect effects of single-layer TMDs, and realizes efficient intrinsic radiation recombination (photon) luminescence of excitons by selecting the composition of two-dimensional transition metal chalcogenides and the corresponding crystal plane of the sapphire substrate, laying the foundation for the application of high-brightness, narrow-spectrum light-emitting diodes based on two-dimensional materials.
[0039] The oxygen-containing atmosphere includes but is not limited to an oxygen atmosphere, and may also be air.
[0040] In some alternative embodiments, the oxygen-containing atmosphere comprises air.
[0041] The a-plane sapphire substrate and the c-plane sapphire substrate are annealed in an air atmosphere, and the nanoscale steps on the surface of the obtained sapphire substrate are regularly distributed. At this time, the single layer of two-dimensional transition metal chalcogenide corresponding to the crystal plane is mechanically peeled to its surface, which not only can suppress the intrinsic defects of the two-dimensional transition metal chalcogenide of the corresponding composition, but also has low cost.
[0042] In some optional embodiments, the temperature of the annealing treatment is 1000°C-1200°C.
[0043] The annealing time within the above annealing temperature is short, energy consumption is reduced, and the modification effect on the sapphire liner is good.
[0044] Illustratively, the temperature of the annealing treatment is any one of 1000° C., 1025° C., 1050° C., 1075° C., and 1200° C., or is between any two values.
[0045] In some optional embodiments, the temperature of the annealing treatment is 1100°C-1200°C.
[0046] The annealing time within the above annealing temperature is short, energy consumption is reduced, and the modification effect on the sapphire liner is good.
[0047] In some optional embodiments, the annealing treatment time is 6 hours to 10 hours.
[0048] Illustratively, the annealing time is any one of 6.0 h, 6.5 h, 7.0 h, 7.5 h, 8.0 h, 8.5 h, 9.0 h, 9.5 h, and 10.0 h, or between any two values.
[0049] The present application also provides a method for suppressing intrinsic defects of two-dimensional transition metal chalcogenides, which comprises:
[0050] growing a two-dimensional transition metal chalcogenide on the surface of an annealed sapphire substrate;
[0051] The annealing treatment includes maintaining the temperature at 800°C-1300°C for 4h-12h in an oxygen-containing atmosphere;
[0052] The two-dimensional transition metal chalcogenide is WS2, and the sapphire substrate is an a-plane sapphire substrate; alternatively, the two-dimensional transition metal chalcogenide is WSe2, and the surface of the sapphire substrate is a c-plane.
[0053] The a-plane sapphire substrate and the c-plane sapphire substrate are kept at 800-1300°C for 4-12 hours and annealed. This facilitates atomic diffusion and crystal structure rearrangement under the action of high-temperature heat treatment, resulting in a regular distribution of nanoscale steps on the surface of the sapphire substrate. The annealed substrate is then used as a growth substrate to grow a two-dimensional transition metal chalcogenide corresponding to its crystal plane. This utilizes interface coupling to suppress the defect effects of the monolayer TMDs. By selecting the composition of the two-dimensional transition metal chalcogenide and the corresponding crystal plane of the sapphire substrate, efficient intrinsic radiative recombination (photon luminescence) of excitons is achieved, thereby suppressing the intrinsic defects of the two-dimensional transition metal chalcogenide.
[0054] Illustratively, the temperature of the annealing treatment is any one of 800° C., 900° C., 1000° C., 1100° C., 1200° C., 1300° C., or between any two values.
[0055] Exemplarily, the annealing time is any one of 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, and 12 h, or between any two values.
[0056] That is, the control method provided in this application utilizes interface coupling to suppress the defect effects of single-layer TMDs, and realizes efficient intrinsic radiation recombination (photon) luminescence of excitons by selecting the composition of two-dimensional transition metal chalcogenides and the corresponding crystal plane of the sapphire substrate, laying the foundation for the application of high-brightness, narrow-spectrum light-emitting diodes based on two-dimensional materials.
[0057] The oxygen-containing atmosphere includes but is not limited to an oxygen atmosphere, and may also be air.
[0058] In some alternative embodiments, the oxygen-containing atmosphere comprises air.
[0059] The a-plane sapphire substrate and the c-plane sapphire substrate are annealed in an air atmosphere, and the nanoscale steps on the surface of the obtained sapphire substrate are regularly distributed. At this time, the single layer of two-dimensional transition metal chalcogenide corresponding to the crystal plane is mechanically peeled to its surface, which not only can suppress the intrinsic defects of the two-dimensional transition metal chalcogenide of the corresponding composition, but also has low cost.
[0060] In some optional embodiments, the number of layers of the two-dimensional transition metal chalcogenide is 1.
[0061] That is, the number of layers of the two-dimensional transition metal chalcogenide is a single layer.
[0062] In some optional embodiments, the temperature of the annealing treatment is 1000°C-1200°C.
[0063] The annealing time within the above annealing temperature is short, energy consumption is reduced, and the modification effect on the sapphire liner is good.
[0064] Illustratively, the temperature of the annealing treatment is any one of 1000° C., 1025° C., 1050° C., 1075° C., and 1200° C., or is between any two values.
[0065] In some optional embodiments, the annealing treatment time is 6 hours to 10 hours.
[0066] Illustratively, the annealing time is any one of 6.0 h, 6.5 h, 7.0 h, 7.5 h, 8.0 h, 8.5 h, 9.0 h, 9.5 h, and 10.0 h, or between any two values.
[0067] The method of suppressing intrinsic defects of two-dimensional transition metal chalcogenides of the present application is further described in detail below with reference to the examples.
[0068] Example 1
[0069] The a-plane sapphire substrate was annealed in an air atmosphere at 1150° C. for 6 hours to obtain an annealed a-plane sapphire substrate.
[0070] Mechanically peel the single-layer WS2 sample to the a-plane of the annealed a-plane sapphire substrate.
[0071] Among them, the PL spectrum of the mechanically exfoliated single-layer WS2 on the a-plane sapphire after annealing treatment in Example 1 does not show a defect state luminescence peak at 7K, but only a pure exciton state luminescence peak.
[0072] Example 2
[0073] The c-plane sapphire substrate was annealed in an air atmosphere at 1150° C. for 6 hours to obtain an annealed c-plane sapphire substrate.
[0074] Mechanically exfoliate a single-layer WSe2 sample onto the c-plane of an annealed c-plane sapphire substrate.
[0075] Among them, the PL spectrum of the mechanically exfoliated single-layer WSe2 on the c-plane sapphire after annealing treatment in Example 2 does not show a defect state luminescence peak at 7K, but only a pure exciton state luminescence peak.
[0076] Example 3
[0077] The only difference from Example 1 is that the a-plane sapphire substrate is annealed at 1000° C. for 4 hours in an air atmosphere to obtain an annealed a-plane sapphire substrate.
[0078] Among them, the PL spectrum of the mechanically exfoliated single-layer WS2 on the a-plane sapphire after annealing treatment in Example 3 does not show a defect state luminescence peak at 7K, but only a pure exciton state luminescence peak.
[0079] Example 4
[0080] The a-plane sapphire substrate was annealed in an air atmosphere at 1150° C. for 6 hours to obtain an annealed a-plane sapphire substrate.
[0081] A single layer of WS2 was grown on the a-surface of an annealed a-plane sapphire substrate using a CVD method. The method involved weighing 4 grams of 99.99% pure tungsten trioxide as a tungsten source and placing it in a ceramic boat. A certain amount of 99.9% pure sulfur (to achieve a molar ratio of S:WO3 of 5:1) was weighed and placed in another ceramic boat as a sulfur source. The tungsten source was placed in the constant temperature zone of a horizontal tubular reactor. The annealed a-plane sapphire substrate was placed in the low-temperature zone below the tungsten source. The sulfur source was placed above the tungsten source at the furnace inlet. Before heating, the horizontal tubular reactor was pre-evacuated to remove all air from the reactor. Then, 25 sccm of 99.999% pure argon was introduced, and the system pressure was maintained at 0.5 Torr by adjusting the pumping rate. The system was then heated from room temperature to 880°C over 30 minutes, and then slowly increased from 880°C to 890°C over 5 minutes. When the system temperature reached 730°C, the sulfur source was auxiliary heated. The heating rate was controlled so that the source temperature reached 180°C within 5 minutes. Simultaneously with the heating of the sulfur source, 99.999% pure hydrogen was introduced into the system, maintaining a hydrogen-to-argon ratio of 1:7. The mechanical pumping rate was adjusted to maintain the system pressure at 0.5 Torr. After 50 minutes of reaction, heating was stopped and the system was allowed to cool naturally. When the system temperature dropped to room temperature, the system was shut down and the sample was removed.
[0082] Among them, the PL spectrum of the mechanically exfoliated single-layer WS2 on the a-plane sapphire after annealing treatment in Example 4 does not show a defect state luminescence peak at 7K, but only a pure exciton state luminescence peak.
[0083] Comparative Example 1
[0084] The only difference between it and Example 1 is the substrate:
[0085] The c-plane sapphire substrate is annealed at 1150° C. for 6 hours in an air atmosphere to obtain an annealed c-plane sapphire substrate to replace the annealed a-plane sapphire substrate.
[0086] Comparative Example 2
[0087] The only difference between it and Example 1 is the substrate:
[0088] The silicon oxide / silicon substrate is replaced with the annealed a-plane sapphire substrate, wherein the single-layer WS2 sample is mechanically peeled off to the silicon oxide surface of the silicon oxide / silicon substrate.
[0089] in, Figure 1 The optical images of single-layer WS2 on different substrates of Example 1 and Comparative Examples 1-2 are shown. Figure 1 It can be seen that there is no obvious difference in the single-layer WS2 on different substrates.
[0090] Figure 2 The photoluminescence spectra of single-layer WS2 on different substrates in Example 1 and Comparative Examples 1-2 at 7K and 298K are shown, where: Figure 2 Part a is the WS2 / c-Al2O3 provided in Comparative Example 1, Figure 2 Part b is WS2 / Si2O2 / Si provided in Comparative Example 1, Figure 2 Part c is WS2 / a-Al2O3 provided in Example 1, according to Figure 2 It can be seen that the PL spectrum of the mechanically exfoliated monolayer WS2 on the annealed a-plane sapphire shows no defect state luminescence peak at 7K, but only a pure exciton state luminescence peak (2-2.1eV). However, the PL spectra of the mechanically exfoliated monolayer WS2 on the annealed c-plane sapphire and silicon oxide / silicon substrates both show obvious defect state luminescence peaks (approximately 1.8-2eV) at 7K.
[0091] Comparative Example 3
[0092] The only difference between it and Example 1 is the substrate:
[0093] The a-plane sapphire substrate before annealing is used to replace the a-plane sapphire substrate after annealing.
[0094] Among them, the PL spectrum of the mechanically exfoliated single-layer WS2 on a-plane sapphire before annealing treatment showed an obvious defect state luminescence peak at 7K.
[0095] Comparative Example 4
[0096] The only difference between it and Example 2 is the substrate:
[0097] The a-plane sapphire substrate is annealed in an air atmosphere at 1150° C. for 6 hours to obtain an annealed a-plane sapphire substrate, which is then used to replace the annealed a-plane sapphire substrate.
[0098] Comparative Example 5
[0099] The only difference between it and Example 2 is the substrate:
[0100] The silicon oxide / silicon substrate is replaced with the annealed c-plane sapphire substrate, wherein the single-layer WSe2 sample is mechanically peeled off to the silicon oxide surface of the silicon oxide / silicon substrate.
[0101] in, Figure 3 The optical images of single-layer WSe2 on different substrates in Example 2 and Comparative Examples 4-5 are shown. Figure 3 It can be seen that there is no obvious difference in the single-layer WSe2 on different substrates.
[0102] Figure 4The photoluminescence spectra of single-layer WSe2 on different substrates in Example 2 and Comparative Examples 4-5 at 7K and 298K are shown. Figure 4 Part a is WSe2 / a-Al2O3 provided in Comparative Example 4, Figure 4 Part b is WSe2 / Si2O2 / Si provided in Comparative Example 5, Figure 4 Part c is WSe2 / c-Al2O3 provided in Example 2, according to Figure 4 It can be seen that the PL spectrum of the mechanically exfoliated monolayer WSe2 on the annealed c-plane sapphire shows no defect state luminescence peak at 7K, only a pure exciton state luminescence peak (2-2.1eV). However, the PL spectra of the mechanically exfoliated monolayer WSe2 on the annealed a-plane sapphire and silicon oxide / silicon substrates both show obvious defect state luminescence peaks (approximately 1.8-2eV) at 7K.
[0103] Comparative Example 6
[0104] The only difference between it and Example 2 is the substrate:
[0105] The c-plane sapphire substrate after annealing is replaced with the c-plane sapphire substrate before annealing.
[0106] Among them, the PL spectrum of the mechanically exfoliated single-layer WSe2 on the c-plane sapphire before annealing treatment showed an obvious defect state luminescence peak at 7K.
[0107] Figure 5 AFM images of the c-plane sapphire substrate before and after annealing. Figure 5 Part a is an AFM image of the c-plane sapphire substrate before annealing used in Comparative Example 6. Figure 5 Part b is the AFM image of the c-plane sapphire substrate after annealing used in Example 2. Figure 5 It can be seen that the surface of the c-plane sapphire substrate is smoother after annealing.
[0108] In summary, the present application provides a method for regulating the intrinsic defects of two-dimensional transition metal chalcogenides. This method utilizes interface coupling to suppress the defect effects of single-layer TMDs, and achieves efficient intrinsic radiative recombination (photon) luminescence of excitons by selecting a suitable substrate, laying the foundation for the application of high-brightness, narrow-spectrum light-emitting diodes based on two-dimensional materials.
[0109] The above are merely specific embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.
Claims
1. A method for suppressing intrinsic defects in two-dimensional transition metal chalcogenides, characterized in that: include: Mechanically exfoliating a monolayer of two-dimensional transition metal chalcogenide onto the surface of an annealed substrate; The annealing treatment includes maintaining the temperature at 800° C. to 1300° C. for 4 to 12 hours in an oxygen-containing atmosphere; Wherein, the two-dimensional transition metal sulfide compound is WS2, and the substrate is an a-plane sapphire substrate; or, the two-dimensional transition metal sulfide compound is WSe2, and the substrate is a c-plane sapphire substrate.
2. The control method according to claim 1, wherein The oxygen-containing atmosphere includes air.
3. The control method according to claim 1, characterized in that The temperature of the annealing treatment is 1000°C-1200°C.
4. The control method according to claim 1, wherein The temperature of the annealing treatment is 1100°C-1200°C.
5. The control method according to any one of claims 1 to 4, characterized in that: The annealing treatment time is 6h-10h.
6. A method for suppressing intrinsic defects in two-dimensional transition metal chalcogenides, characterized in that: include: growing a two-dimensional transition metal chalcogenide on the surface of an annealed sapphire substrate; The annealing treatment comprises maintaining the temperature at 800° C. to 1300° C. for 4 h to 12 h in an oxygen-containing atmosphere; The two-dimensional transition metal chalcogenide is WS2, and the sapphire substrate is an a-plane sapphire substrate; or, the two-dimensional transition metal chalcogenide is WSe2, and the surface of the sapphire substrate is a c-plane.
7. The control method according to claim 6, characterized in that: The oxygen-containing atmosphere includes air.
8. The control method according to claim 6, characterized in that: The two-dimensional transition metal chalcogenide compound has one layer.
9. The control method according to claim 6, characterized in that: The temperature of the annealing treatment is 1000°C-1200°C.
10. The control method according to claim 6, characterized in that: The annealing treatment time is 6h-10h.