A semi-metallic nanoparticle-modified two-dimensional material photodetector

Abstract

The application discloses a kind of two-dimensional material photoelectric detector based on semi-metallic nanoparticles modification, belong to two-dimensional semiconductor material technical field.The preparation method includes the following steps: using porous positive grade aluminum oxide (AAO) constructs MO3 (M represents Mo, W) nanoparticle structure array, then MO x(x<3) Semi-metallic nanoparticles, semi-metallic particles are combined with two-dimensional materials to prepare photoelectric detectors.Compared with metal nanoparticles, the plasmonic effect of semi-metallic nanoparticles can reach the mid-infrared band with doping at a certain concentration, while the plasmonic effect of metal nanoparticles is mainly in the visible light band, so semi-metallic plasmonic materials have great potential in developing high-performance infrared detectors.The method is realized at room temperature, the particle doping concentration is controllable, the shape is regular and uniformly distributed, the operation is simple, the controllability is strong, and the practicality is strong.

Description

Technical Field

[0001] This invention relates to a two-dimensional material photodetector modified with semi-metallic nanoparticles, belonging to the field of two-dimensional semiconductor material technology. Background Technology

[0002] Two-dimensional materials possess numerous advantages, such as large specific surface area, absence of dangling bonds, high carrier mobility, and high on / off ratio, making them highly promising for photoelectric detection. To date, photodetectors based on two-dimensional materials have been extensively developed. Compared to similar products made from bulky semiconductors, two-dimensional photodetectors are flexible, transparent, and inexpensive. However, their atomic thickness results in low photoresponsivity and quantum yield, severely limiting the performance of two-dimensional material optoelectronic devices.

[0003] Currently, a promising approach is to combine two-dimensional materials with metallic nanostructures. Localized surface plasmons (LSPRs) in metallic nanostructures, at their resonant wavelengths, confine light energy to the nanoscale, leading to a significant enhancement of the electromagnetic field at the end of the nanostructure. Two-dimensional materials can fully utilize this localized electromagnetic field to improve the performance of two-dimensional optoelectronic devices. For example, the paper "Plasmon-Enhanced SnSe2 Photodetector by Non-Contact Ag Nanoparticles [Small, 2021, 17(35): 2102351]" uses ion implantation to embed Ag nanoparticles on a substrate, exchanging energy through plasmon resonance energy transfer, maximizing the lattice integrity and performance of SnSe2. The responsivity of this device is 881 times higher than that of a pure SnSe2 photodetector, and it can detect lasers at 2200 nm. The paper, titled "Enhancement of MoTe2 near-infrared absorption with gold hollow nanorods for photodetection [Nano Research, 2020, 13(6): 1636-1643]", reports a photodetector composed of Au hollow nanorods and MoTe2. Unlike typical Au nanoparticles, the resonant absorption peak of these nanorods is around 1000 nm, attributed to their unique structure. The near-infrared response enhancement factor of this device is approximately 60.

[0004] While noble metal nanomaterials such as gold and silver exhibit excellent plasmon effects in the visible light band, their non-radiative losses in the ultraviolet band and shielding effects in the infrared band pose significant challenges for infrared detection. Furthermore, the high cost of noble metal nanoparticles limits their practical applications. In contrast, metallic semi-metallic nanoparticle plasmon materials hold great potential for developing high-performance infrared detectors. However, selecting the appropriate material and employing a controllable process to prepare semi-metallic nanoparticles and integrate them with two-dimensional materials to further broaden the spectral density of two-dimensional photodetectors remains a challenge. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for modifying two-dimensional materials with semi-metallic nanoparticles into photodetectors. This method transforms MO3 (M represents Mo or W) nanoparticles into MO3 nanoparticles at room temperature through hydrogen plasma treatment. x(x<3) Semi-metallic nanoparticles are uniform in size, highly controllable, easy to operate, environmentally friendly and pollution-free, and highly practical.

[0006] The first objective of this invention is to provide a two-dimensional material photodetector modified with semi-metallic nanoparticles, the method comprising the following steps:

[0007] (1) MO3 (M represents Mo and W) nanoparticles were prepared on a silicon wafer using a porous anodic aluminum oxide (AAO) mask method. This silicon wafer was placed in a plasma chamber containing non-parallel plate capacitively coupled plasma generated by a planar helical inductive antenna, and the chamber was evacuated to a vacuum level of 8.0 × 10⁻⁶. -3 Below Pa; H2 is introduced, and the plasma radio frequency power supply is turned on to excite the plasma, transforming the MO3 nanoparticles on the silicon wafer surface into MO3 nanoparticles. x(x<3) Semi-metal nanoparticles; using a self-made transfer platform, two-dimensional materials are transferred onto a silicon wafer with semi-metal nanoparticles attached, thereby obtaining a two-dimensional material photodetector modified with semi-metal nanoparticles at the bottom layer.

[0008] (2) The two-dimensional material sheet is transferred to the silicon wafer by mechanical peeling, and then a two-dimensional material photodetector modified with top half-metal nanoparticles is prepared on the silicon wafer with the two-dimensional material sample attached by the method described in step 1.

[0009] In one embodiment, the MO3 (M represents Mo, W) nanoparticles have a size of 5-30 nm.

[0010] In one implementation, the MO x(x<3) The semi-metallic nanoparticles are 5-30 nm in size.

[0011] In one embodiment, the two-dimensional material includes MoS2, MoSe2, WSe2, WS2, Graphene, etc.

[0012] In one embodiment, the preparation method of the MoS2 and Graphene sample includes any one or more of the following: mechanical exfoliation, sputtering, chemical vapor deposition, plasma-enhanced vapor deposition, low-pressure chemical vapor deposition, molecular beam epitaxy, and atomic layer deposition.

[0013] In one embodiment, the substrate silicon wafer is cleaned by: ultrasonically cleaning the substrate in acetone for 5 minutes at a frequency of 25 kHz to remove surface organic matter. Then, the substrate is sequentially ultrasonically cleaned in ethanol and deionized water for 5 minutes each, followed by baking at 350°C for 30 minutes using a heating platform to remove residues such as acetone and ethanol.

[0014] In one embodiment, the excited hydrogen plasma is a non-parallel plate capacitively coupled plasma generated by a planar spiral inductor antenna. The plasma radio frequency power supply frequency is 0.5-2MHz. At this time, the silicon wafer with MO3 nanoparticles on its surface needs to be placed horizontally in the plasma chamber, parallel to the planar spiral inductor antenna.

[0015] In one embodiment, the power range of the plasma radio frequency power supply is 50-600W.

[0016] In one implementation, the H2 flow rate is 5-35 sccm (standard milliliters / minute), and the working pressure is 5-30 Pa.

[0017] In one embodiment, the hydrogen plasma treatment time is 5-30 minutes.

[0018] This invention utilizes the above method to prepare a two-dimensional photodetector modified with semi-metallic nanoparticles.

[0019] A second objective of this invention is to provide a photodetector comprising a two-dimensional material photodetector modified with semi-metallic nanoparticles prepared by the above method.

[0020] A third objective of this invention is to provide an optoelectronic device comprising a two-dimensional material photodetector modified with semi-metallic nanoparticles prepared by the above method.

[0021] In one embodiment, the optoelectronic device is fabricated by depositing Ni / Au (5nm / 50nm) source / drain electrodes using electron beam lithography and electron beam evaporation on a MoS2 or Graphene sample of semi-metallic nanoparticles.

[0022] The fourth objective of this invention is to provide applications of two-dimensional material photodetectors modified with semi-metallic nanoparticles prepared by the above-described preparation method in the micro-nano and semiconductor fields.

[0023] The beneficial effects of this invention are:

[0024] 1. The structure and size of MO3 (M represents Mo and W) nanoparticles and semi-metallic nanoparticles are controllable, and the plasma-treated nanoparticles are uniformly and regularly distributed.

[0025] 2. Two-dimensional material photodetectors modified with semi-metallic nanoparticles can detect visible light and mid-infrared wavelengths.

[0026] 3. The plasma is gentle, and the entire process will not bombard or thin the sample, causing no impact on the material. The method is simple.

[0027] 4. Compared with precious metal nanoparticles such as Au and Ag, it has the advantages of low raw material cost and environmental protection without pollution.

[0028] 5. This method has good repeatability and strong controllability, and can realize the production of half-metal nanoparticles WOx. (x<3) Modified two-dimensional material photodetectors are beneficial to promoting the development of two-dimensional materials in the micro-nano and semiconductor industries. Attached Figure Description

[0029] Figure 1 Atomic force microscopy (AFM) images of WO3 nanoparticle arrays (a: morphology, b: thickness).

[0030] Figure 2 semi-metallic nanoparticles WOx (x<3) Atomic force microscopy (AFM) images of the array (a: topography, b: thickness).

[0031] Figure 3 This is an X-ray photoelectron spectroscopy image of a WO3 nanoparticle array.

[0032] Figure 4 semi-metallic nanoparticles WOx (x<3) X-ray photoelectron spectroscopy image of the array.

[0033] Figure 5 Schematic diagram of two-dimensional material devices modified with bottom and top semi-metallic nanoparticles (where a, b, and c are WOx). (x<3) -Graphene photodetector, WOx (x<3) -MoS2 photodetector, MoS2-WOx (x<3) (Schematic diagram of a photodetector).

[0034] Figure 6 Photocurrent diagrams of intrinsic graphene photodetectors under different lasers.

[0035] Figure 7 Wavelength 637nm WOx (x<3) - Photocurrent diagram of a Graphene photodetector.

[0036] Figure 8 940nm wavelength WOx (x<3) - Photocurrent diagram of a Graphene photodetector.

[0037] Figure 9 Intrinsic MoS2 and MoS2-WO x(x<3) The Raman spectrum.

[0038] Figure 10 Photocurrent diagram of an intrinsic molybdenum disulfide photodetector with a wavelength of 940 nm.

[0039] Figure 11 940nm wavelength semi-metallic nanoparticles MoS2-WO x(x<3) Photocurrent diagram of a photodetector.

[0040] Figure 12 A bar chart comparing the photocurrent of photodetectors at different locations of 940nm semi-metallic nanoparticles.

[0041] Figure 13 A bar chart comparing the photocurrent of photodetectors with different sizes (5nm, 10nm, 15nm) of semi-metallic nanoparticles at a wavelength of 940nm. Detailed Implementation

[0042] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0043] The schematic diagram of the photodetector of this invention is shown below. Figure 5 ,Depend on Figure 5 It can be seen that: semi-metallic nanoparticles WOx (x<3) Photodetectors are fabricated by combining them with two-dimensional materials.

[0044] Example 1

[0045] The experimental equipment in this embodiment, a non-parallel plate capacitively coupled plasma chemical deposition system, has been disclosed in a patent published on June 10, 2015, with publication number CN104694906A.

[0046] based on Figure 5 A type of semi-metallic nanoparticle WO x(x<3) - The Graphene photodetector method includes the following steps:

[0047] (1) Substrate cleaning: In this embodiment, a silicon wafer coated with a 300nm silicon dioxide layer is used as the substrate. The substrate is ultrasonically cleaned in acetone for 5 minutes at an ultrasonic frequency of 25KHz to remove surface organic matter. Then, the substrate is ultrasonically cleaned in ethanol and deionized water for 5 minutes in sequence, and then baked at 350°C for 30 minutes using a heating platform to remove acetone, ethanol and other residues.

[0048] (2) Sample preparation: Graphene samples were obtained on polydimethylsiloxane (PDMS) using a mechanical exfoliation method. The PDMS-coated graphene samples were then transferred to a cleaned silicon wafer using a transfer platform. After standing for 3 minutes to allow adhesion, the PDMS was removed, resulting in a thin-layer graphene sample (approximately 3 layers thick). Then, approximately 10 nm WO3 nanoparticles were deposited on the thin-layer graphene sample using a porous anodic aluminum oxide (AAO) mask method, followed by plasma treatment to obtain semi-metallic nanoparticles. At this point, WO3 nanoparticles were deposited on the thin-layer graphene sample. x(x<3) -Graphene samples; finally, Ni / Au (5nm / 50nm) electrodes were deposited using ultraviolet lithography and electron beam evaporation to fabricate FET devices;

[0049] (3) Sample processing: The WO3 nanoparticles obtained in step (2) are placed in a plasma vacuum chamber (high vacuum environment). At this time, the substrate with WO3 nanoparticles needs to be placed horizontally and parallel to the planar spiral inductor antenna; the vacuum is evacuated to 8.0 × 10⁻⁶. -3 Below Pa, H2 gas was introduced at a flow rate of 10 sccm and a working pressure of 15 Pa. The plasma radio frequency power supply was turned on at a frequency of 2 MHz and the power was adjusted to 450 W. Timing was started after ignition. The processing time was 6 minutes, yielding WO4 semi-metallic nanoparticles. x(x<3) ;

[0050] (4) Sample characterization: The size and dimensions of the nanoparticles were characterized using atomic force microscopy. The characterization results are shown in […]. Figure 1 and Figure 2 X-ray photoelectron spectroscopy (XPS) was used to study WO3 nanoparticles and semi-metallic nanoparticles. x Elemental content characterization was performed, and the results are shown in [the table below]. Figure 3 and Figure 4 .from Figure 1 and Figure 2 It can be seen that the WO3 nanoparticles are evenly and regularly distributed, with a particle size of about 10 nm. Figure 3 and Figure 4 XPS characterization confirmed that WO4 after hydrogen plasma treatment x W in the sample 4f 5+ The presence of the signal indicates that the semi-metallic nanoparticles WO x(x<3) .

[0051] (5) Photoelectric testing: Using a Keithley 2643B digital source meter at 637nm and 940nm laser wavelengths, V ds Photoelectric performance test at 1V. Figure 6 This is a photocurrent graph of an intrinsic graphene photodetector. As can be seen from the graph, intrinsic graphene at V... ds No significant optical response was observed with 1V, 637nm, and 940nm lasers. Figure 7 It is WO x(x<3) -Graphene photodetector in 637nm laser V ds Photocurrent curve at 1V, compared Figure 6 It is evident that the light response has improved, exhibiting a good square wave. Furthermore, the light current I... light An increase of approximately 90 times. Figure 8 940nm laser V ds The photocurrent curve at 1V shows a significant photoresponse at a light current of 9.384μW. light =4×10 -7 A.

[0052] Example 2

[0053] (1) The substrate cleaning steps are the same as in Example 1.

[0054] (2) Sample Preparation: In this embodiment, 15 nm WO3 nanoparticles were first deposited on a substrate using electron beam evaporation via a porous anodic aluminum oxide (AAO) mask method, followed by plasma treatment to obtain semi-metallic nanoparticles. A thin layer of MoS2 was obtained on polydimethylsiloxane (PDMS) using mechanical exfoliation. Then, the mechanically exfoliated MoS2 thin layer (approximately 7 layers thick) on PDMS was transferred to the substrate containing the WO3 nanoparticles using a transfer platform. x(x<3) On the substrate, let it stand for 3 minutes; after the two have adhered, remove the PDMS, at which point MoS2-WO3 is formed on the silicon substrate. x(x<3) Samples were then deposited; finally, FET devices were fabricated using ultraviolet lithography and electron beam evaporation to deposit Ni / Au (5nm / 50nm) electrodes.

[0055] (3) Sample preparation: Same as step 3 in Example 1

[0056] (4) Sample characterization: The heterojunction was characterized using Raman fluorescence spectroscopy. The characterization results are shown in […]. Figure 9 This embodiment uses molybdenum disulfide with a thickness of approximately 7 layers. From Figure 9 It can be seen that, with the semi-metallic nanoparticles WOx (x<3) The Raman spectrum of molybdenum disulfide did not change after binding, indicating that the sample lattice remained intact and was not damaged.

[0057] (5) Photoelectric testing: Using a Keithley 2643B digital source meter at a laser wavelength of 940nm V ds Photoelectric performance test at 1V. Figure 10 This is a photocurrent graph of an intrinsic molybdenum disulfide photodetector. From the graph, it can be seen that the intrinsic molybdenum disulfide photodetector at V... ds =1V has a very poor and unstable response to 940nm laser. Figure 11 It is MoS2-WO x(x<3) Photocurrent graph of photodetector, comparison Figure 9 It can be seen that the light response is improved, and under the same light power, the light current I... light From 1×10 -8 A increased to 1.407 × 10 -6 A times.

[0058] Example 3

[0059] (1) The substrate cleaning steps are the same as in Example 2.

[0060] (2) Sample preparation: MoS2 samples were obtained on polydimethylsiloxane (PDMS) using a mechanical exfoliation method. The MoS2 samples on PDMS were then transferred to a cleaned silicon wafer using a transfer platform. After standing for 3 minutes to allow them to adhere, the PDMS was removed, resulting in a thin-layer MoS2 sample (approximately 8 layers thick). Then, approximately 10 nm WO3 nanoparticles were deposited on the thin-layer MoS2 sample using a porous anodic aluminum oxide (AAO) mask method, followed by plasma treatment to obtain semi-metallic nanoparticles. At this point, WO3 nanoparticles were deposited on the thin-layer MoS2 sample. x(x<3) -MoS2 sample; finally, Ni / Au (5nm / 50nm) electrodes were deposited using ultraviolet lithography and electron beam evaporation to fabricate FET devices;

[0061] (3) Sample processing: Same as step 3 in Example 1.

[0062] (4) Photoelectric testing: Using a Keithley 2643B digital source meter at a laser wavelength of 940nm V ds Photoelectric performance test at 1V. Figure 12The photocurrent I of the semi-metallic particles located at different positions in the bottom and top layers of the sample. ph＝ I light -I dark The bar chart shows that when the laser power is 5uW, the top layer WO x(x<3) -MoS2 photodetector I ph It is 1.474×10 -8 A, while the underlying MoS2-WO x(x<3) device I ph 2.87×10 -7 A, an improvement of approximately 10 times. This indicates that the semi-metallic particles at the bottom layer exhibit the best photoelectric performance.

[0063] Example 4

[0064] (1) The substrate cleaning steps are the same as in Example 2.

[0065] (2) Sample Preparation: In this embodiment, WO3 nanoparticles of 5 nm and 15 nm were first deposited on a substrate using electron beam evaporation with a porous anodic aluminum oxide (AAO) mask method, followed by plasma treatment to obtain semi-metallic nanoparticles. A thin layer of MoS2 was obtained on polydimethylsiloxane (PDMS) using mechanical exfoliation. Then, the mechanically exfoliated MoS2 thin layer (approximately 7 layers thick) on PDMS was transferred to the substrate with the attached semi-metallic nanoparticles using a transfer platform. x(x<3) On the substrate, let it stand for 3 minutes; after the two have adhered, remove the PDMS, at which point MoS2-WO3 is formed on the silicon substrate. x(x<3) Samples were then deposited; finally, FET devices were fabricated using ultraviolet lithography and electron beam evaporation to deposit Ni / Au (5nm / 50nm) electrodes.

[0066] (3) Sample processing: Same as step 3 in Example 1.

[0067] (4) Photoelectric testing: Using a Keithley 2643B digital source meter at a laser wavelength of 940nm, V ds Photoelectric performance was tested at 1V and laser power of 1μW, 5μW, and 10μW. Figure 13 The photocurrent I of the photodetector is prepared by using semi-metallic particles with thicknesses of 5 nm, 10 nm, and 15 nm. ph The bar chart shows that when the laser power is 5µW, the photodetector I for 5nm particles... ph =5.47375×10 -8 A, 10nm particle photodetector I ph =2.87×10 -7 A, 15nm particle photodetector I ph =8.47×10-8 A shows that 10nm particles produce the best device performance, and that different sizes of semi-metallic particles have a significant impact on the device.

[0068] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A two-dimensional material photodetector modified with semi-metallic nanoparticles, characterized in that, The method for fabricating the two-dimensional material photodetector includes the following steps: (The substrate is a silicon wafer coated with a silicon dioxide layer.) MO3 nanoparticles were prepared on a silicon wafer using a porous anodic alumina mask method. This silicon wafer was then placed in a plasma chamber containing non-parallel plate capacitively coupled plasma generated by a planar helical inductive antenna. The chamber was evacuated to a vacuum level of 8.0 × 10⁻⁶. -3 Below Pa; H2 is introduced, and the plasma radio frequency power supply is turned on to excite the plasma, transforming the MO3 nanoparticles on the silicon wafer surface into MO3 nanoparticles. x（x<3） Semi-metal nanoparticles; Two-dimensional materials are transferred onto a silicon wafer with semi-metal nanoparticles attached using a transfer platform, with the semi-metal nanoparticles positioned below the two-dimensional material sample. Ni / Au electrodes are deposited using ultraviolet lithography and electron beam evaporation processes to obtain a two-dimensional material photodetector modified with bottom semi-metal nanoparticles. In the MO3 nanoparticles, M represents Mo and W; MO x（x<3） The size of the semi-metallic nanoparticles is 5-30 nm; The two-dimensional materials mentioned include MoS2, MoSe2, WSe2, WS2, or graphene.

2. The two-dimensional material photodetector modified with semi-metallic nanoparticles according to claim 1, characterized in that, MO x（x<3） The size of the semi-metallic nanoparticles is 5 nm, 10 nm, or 15 nm.

3. The two-dimensional material photodetector modified with semi-metallic nanoparticles according to claim 1, wherein the excited mild hydrogen plasma is a non-parallel plate capacitively coupled plasma generated by a planar spiral inductor antenna, the plasma radio frequency power supply frequency is 0.5-2MHz, and a silicon wafer with MO3 nanoparticles on its surface is placed horizontally in the plasma chamber, parallel to the planar spiral inductor antenna.

4. The two-dimensional material photodetector modified with semi-metallic nanoparticles according to claim 1, characterized in that, The power of the radio frequency power supply for plasma processing is 50-600 W.

5. The two-dimensional material photodetector modified with semi-metallic nanoparticles according to claim 1, characterized in that, The flow rate of H2 introduced is 5-35 sccm, and the working pressure is 5-30 Pa.

6. The two-dimensional material photodetector modified with semi-metallic nanoparticles according to claim 1, characterized in that, The plasma treatment time is 5-30 minutes.

7. An optoelectronic device, characterized in that, A two-dimensional material photodetector modified with semi-metallic nanoparticles as described in any one of claims 1-6.

8. The application of the two-dimensional material photodetector modified with semi-metallic nanoparticles as described in any one of claims 1-6 in the micro-nano and semiconductor fields.

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