A wide-spectrum photodetector and a preparation method thereof

Abstract

The application provides a wide-spectrum photodetector and a preparation method thereof, and relates to the technical field of photodetectors.The preparation method comprises the following steps: preparing an interdigital electrode on a conductive substrate; depositing perovskite quantum dots between the interdigital electrode; and coating a protective layer on the interdigital electrode with the deposited perovskite quantum dots.The interdigital electrode structure increases the contact area between the photosensitive material and the electrode, which can effectively improve the collection efficiency of photo-generated carriers, thereby improving the sensitivity of the photodetector.The perovskite quantum dots, as the photosensitive material, have wide-spectrum absorption characteristics and high quantum efficiency, which can widen the spectral response range of the photodetector.The protective layer can effectively isolate the influence of the external environment on the perovskite quantum dots, improve the stability of the device, and prolong the service life.A high-performance, stable wide-spectrum photodetector is prepared.

Description

Technical Field

[0001] This invention relates to the field of photodetector technology, and in particular to a broadband photodetector and its fabrication method. Background Technology

[0002] Pulsed laser deposition (PLD) uses a pulsed laser to sputter a solid target in a vacuum or special atmosphere, and the sputtered plasma plume is deposited onto a substrate above the target to form a nanoparticle thin film. The nanofilm particles prepared by this technique have advantages such as good uniformity, stable composition, and high purity, and are currently used in the preparation of nanomaterials.

[0003] Photodetectors are key devices that convert optical signals into electrical signals, and they have wide applications in many fields, such as image sensing, optical communication, environmental monitoring, and biomedicine. Broadband photodetectors, which can respond to optical signals over a wide wavelength range, have received increasing attention in recent years due to their importance in various applications.

[0004] Photodetectors in specific wavelength bands can meet the needs of different fields. For example, UV-vis photodetectors can meet the needs of astronomical detection or storage; visible light and near-infrared photodetectors are mainly used in consumer electronics and video recording. However, current technology lacks the ability to achieve broadband photodetectors with a wider spectral response and spectral characteristics.

[0005] Therefore, it is necessary to improve existing broadband photodetector technology to overcome the above problems and realize broadband photodetectors with wider spectral response and spectral characteristics. Summary of the Invention

[0006] To overcome the problems existing in related technologies, one of the objectives of this invention is to provide a method for fabricating a broadband photodetector. This method solves the problems existing in the prior art through the synergistic effect of interdigitated electrodes, perovskite quantum dots and protective layers, and achieves the fabrication of a high-performance and high-stability broadband photodetector.

[0007] A method for fabricating a broadband photodetector includes the following steps:

[0008] Interdigitated electrodes are fabricated on a conductive substrate;

[0009] Perovskite quantum dots are deposited between the interdigitated electrodes;

[0010] A protective layer is coated on the interdigitated electrode on which the perovskite quantum dots are deposited.

[0011] The interdigitated electrode structure increases the contact area between the photosensitive material and the electrode, effectively improving the collection efficiency of photogenerated carriers and thus enhancing the sensitivity of the photodetector. Perovskite quantum dots, as photosensitive materials, possess broad spectral absorption characteristics and high quantum efficiency, which can broaden the spectral response range of the detector. Coating with a protective layer can effectively isolate the perovskite quantum dots from the influence of the external environment, improving device stability and extending lifespan. This enables the fabrication of high-performance, stable, broad-spectrum photodetectors.

[0012] Furthermore, the method for depositing perovskite quantum dots is a transmission pulsed laser deposition method, in which the laser is a femtosecond laser;

[0013] The output power of the femtosecond laser is 10W to 30W;

[0014] The pulse width of the femtosecond laser is 350 fs to 10 ps;

[0015] The pulse repetition frequency range of the femtosecond laser is from 1MHz to 50MHz;

[0016] The pulse energy of the femtosecond laser is from 10 μJ to 80 μJ.

[0017] Transmission-based pulsed laser deposition, particularly using femtosecond lasers for perovskite quantum dot deposition, allows for precise control of deposition thickness and uniformity. The extremely short pulse width of femtosecond lasers reduces thermal effects, preventing damage to the perovskite quantum dots and thus ensuring the material's excellent photoelectric properties. This limited range of laser parameters enables the production of high-quality perovskite quantum dot films, ultimately improving the performance of photodetectors.

[0018] Furthermore, the method for perovskite quantum dot deposition is magnetically focused transmission pulsed laser deposition.

[0019] Furthermore, in magnetically focused transmission pulsed laser deposition, a uniform magnetic field with a magnetic field strength of 200 to 2000 Gs is used.

[0020] Preferably, in magnetically focused transmission pulsed laser deposition, the magnetic field strength is 1545 Gs.

[0021] A photoelectric sensor was deposited under an applied magnetic field strength of 1545 Gs. The photodetector fabricated using this magnetic field strength exhibited a detectivity (D*) of 3.5 × 10⁻⁶ at 450 nm @ 5 V. 10 Jones measured its response rate (R) to be 56.6 mW / cm². 2 .

[0022] Furthermore, the conductive substrate is a gold-plated glass sheet with a thickness of 0.3 mm to 1.0 mm and a gold plating layer thickness of 200 nm to 800 nm.

[0023] Using gold-plated glass sheets as conductive substrates, and limiting their thickness and the range of gold plating thickness, ensures good conductivity and light transmittance. A suitable substrate thickness provides sufficient mechanical strength, while a suitable gold plating thickness balances conductivity and cost. This is beneficial for improving device performance and reducing manufacturing costs.

[0024] Furthermore, the length of the interdigital electrode is 3mm to 10mm, the width is 9mm to 30mm, and the filling gap of the interdigital electrode is 20μm to 80μm.

[0025] By defining the length, width, and gap between the interdigitated electrodes, the matching between the electrode structure and the perovskite quantum dot layer can be optimized, thereby improving the collection efficiency of photogenerated carriers and the response speed of the device. Appropriate interdigital gaps can balance light absorption and carrier collection, ultimately improving the performance of the photodetector.

[0026] Furthermore, the interdigitated electrodes are prepared by laser etching, photolithography, or sputtering deposition.

[0027] It offers a variety of methods for fabricating interdigitated electrodes, such as laser etching, photolithography, or sputtering deposition. Appropriate fabrication processes can be selected according to actual needs, improving fabrication flexibility and reducing fabrication costs.

[0028] Furthermore, the perovskite quantum dots are CsPbBr3 quantum dots, CsPbI3 quantum dots, or CsPbCl3 quantum dots.

[0029] By identifying the types of perovskite quantum dots, such as CsPbBr3, CsPbI3, or CsPbCl3, appropriate materials can be selected for different spectral detection needs, thereby achieving high-sensitivity detection in specific wavelength bands.

[0030] Furthermore, the perovskite quantum dots are CsPbBr3 quantum dot powder.

[0031] Furthermore, the protective layer is polydimethylsiloxane, epoxy resin, or UV-curable resin, and is applied by spin coating, spraying, or dip coating.

[0032] It offers a variety of protective layer materials and coating methods, allowing users to select appropriate materials and processes based on actual needs, thereby improving device stability and fabrication flexibility.

[0033] Furthermore, the protective layer is polydimethylsiloxane, which is coated by spin coating, with a curing temperature of 50°C to 80°C and a curing time of 10 to 15 hours.

[0034] Furthermore, the thickness of the protective layer is 25 μm to 40 μm.

[0035] This defined range of protective layer thickness strikes a balance between protective effectiveness and device performance. An excessively thick protective layer may affect the photodetector's light response speed, while an excessively thin protective layer may not be able to effectively isolate the device from the external environment.

[0036] A second objective of this invention is to provide a broadband photodetector, fabricated based on the broadband photodetector fabrication method described above, comprising:

[0037] Conductive substrate;

[0038] Interdigitated electrodes are disposed on the conductive substrate;

[0039] A perovskite quantum dot layer is deposited between the interdigitated electrodes;

[0040] A protective layer covers the perovskite quantum dot layer and the interdigitated electrodes.

[0041] Furthermore, the protective layer is made of polydimethylsiloxane, and the perovskite quantum dot layer is made of CsPbBr3 quantum dots.

[0042] Using polydimethylsiloxane as a protective layer material can effectively isolate the effects of the external environment on perovskite quantum dots, improving device stability. Using CsPbBr3 quantum dots as a photosensitive material enables high-sensitivity detection in the visible light band.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention provides a method for fabricating a broadband photodetector, comprising three steps: fabricating interdigitated electrodes on a conductive substrate, depositing perovskite quantum dots, and coating a protective layer. The interdigitated electrode structure increases the contact area between the photosensitive material and the electrode, effectively improving the collection efficiency of photogenerated carriers and thus enhancing the sensitivity of the photodetector. Perovskite quantum dots, as photosensitive materials, possess broadband absorption characteristics and high quantum efficiency, which can broaden the spectral response range of the detector. The protective coating effectively isolates the perovskite quantum dots from the influence of the external environment, improving device stability and extending lifespan. This method enables the fabrication of a high-performance, stable broadband photodetector. Attached Figure Description

[0045] Figure 1This is a schematic diagram of the magnetic focusing transmission pulsed laser deposition apparatus provided in the embodiments of this application.

[0046] Figure 2 This is a schematic diagram of the photodetector fabricated in the embodiments of this application.

[0047] Figure 3 The XRD patterns of the deposits obtained by bombarding CsPbBr3 quantum dot powder with femtosecond laser under different magnetic field strengths are shown in the embodiments of this application.

[0048] Figure 4 This refers to the electrical signal response of a high-stability broadband photodetector obtained by magnetic focusing transmission pulsed laser deposition technology under a magnetic field strength of 310 Gs provided in this application embodiment under a 265 nm light source.

[0049] Figure 5 This refers to the electrical signal response of a highly stable broadband photodetector obtained by magnetic focusing transmission pulsed laser deposition technology under a magnetic field strength of 1237 Gs provided in this application embodiment under a 450 nm light source.

[0050] Figure 6 The electrical signal response of the highly stable broadband photodetector obtained by magnetic focusing transmission pulsed laser deposition technology under a magnetic field strength of 771 Gs provided in this application embodiment is shown under an 800 nm light source.

[0051] Figure 7 The stability of the high-stability broadband photodetector obtained by the magnetic focusing transmission pulsed laser deposition technique under a magnetic field strength of 310 Gs provided in the embodiments of this application;

[0052] Figure 8 This is a flowchart illustrating a method for fabricating a broadband photodetector provided in an embodiment of this application. Detailed Implementation

[0053] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0054] Example

[0055] like Figures 1 to 8 As shown, this embodiment provides a method for fabricating a broadband photodetector, which includes the following steps:

[0056] Step 100: Fabricate interdigitated electrodes on a conductive substrate;

[0057] Step 200: Deposit perovskite quantum dots between the interdigitated electrodes;

[0058] Step 300: Coat the interdigitated electrode on which the perovskite quantum dots are deposited with a protective layer.

[0059] In step 200, the method for depositing perovskite quantum dots is a transmission pulsed laser deposition method, wherein the laser in the transmission pulsed laser deposition method is a femtosecond laser;

[0060] The output power of the femtosecond laser is 10W to 30W;

[0061] The pulse width of the femtosecond laser is 350 fs to 10 ps;

[0062] The pulse repetition frequency range of the femtosecond laser is from 1MHz to 50MHz;

[0063] The pulse energy of the femtosecond laser is from 10 μJ to 80 μJ.

[0064] In step 100, the conductive substrate is a gold-plated glass sheet with a thickness of 0.3 mm to 1.0 mm and a gold plating layer thickness of 200 nm to 800 nm.

[0065] In step 100, the length of the interdigital electrode is 3 mm to 10 mm, the width is 9 mm to 30 mm, and the filling gap of the interdigital electrode is 20 μm to 80 μm.

[0066] In step 100, the interdigitated electrodes are fabricated by laser etching, photolithography, or sputtering deposition.

[0067] In step 200, the perovskite quantum dots are CsPbBr3 quantum dots, CsPbI3 quantum dots, or CsPbCl3 quantum dots.

[0068] In step 300, the protective layer is polydimethylsiloxane, epoxy resin, or UV-curable resin, and is applied by spin coating, spraying, or dip coating.

[0069] In step 300, the thickness of the protective layer is 25 μm to 40 μm.

[0070] More specifically, in this embodiment, a broadband photodetector based on CsPbBr3 quantum dots is fabricated using this method, employing methods such as... Figure 1 The magnetic focusing transmission pulsed laser deposition apparatus shown is used for fabrication. The magnetic focusing transmission pulsed laser deposition apparatus includes an energized solenoid, a moving platform, and a femtosecond laser.

[0071] The preparation process specifically includes:

[0072] Interdigitated electrodes were ablated onto a gold-plated glass slide. The femtosecond laser output power was set to 18W, the pulse width to 532fs, the pulse repetition frequency to 32MHz, and the pulse energy to 35μJ.

[0073] The gold-plated glass plate is 0.8 mm thick, and the gold plating layer is 350 μm thick. It is placed vertically under the femtosecond laser beam with the gold-plated side facing down to facilitate the sputtering deposition of the target material later.

[0074] The mobile electric platform was used to find the optimal laser focus and etch the interdigitated electrodes. The interdigitated electrodes were 5 mm long and 7 mm wide, with a gap of 30 μm, to obtain gold electrodes.

[0075] CsPbBr3 quantum dot electrodes were deposited on a conductive substrate.

[0076] A CsPbBr3 quantum dot powder target, pressed into a sheet, is placed beneath a conductive substrate at a distance of 0.5 mm. The entire apparatus is placed within a solenoid (with a uniform magnetic field). A moving electric platform is used to focus a laser 0.5 mm down onto the target surface for magnetically focused transmission pulsed laser deposition. The femtosecond laser output power is 13 W, the pulse width is 450 fs, the pulse repetition frequency is 30 MHz, the pulse energy is 15 μJ, and the magnetic field strength is 771 Gs. The deposition yields a photoelectric sensor.

[0077] Sealing layer for photoelectric detection devices.

[0078] The obtained photoelectric sensor was placed on a spin coater, and 1 ml of PDMS was dropped onto the surface of the photoelectric sensor. The spin coater was run at a low speed of 500 rpm for 5 seconds and at a high speed of 3000 rpm for 20 seconds to obtain a protective layer with a thickness of 500 μm. The device was then transferred to a 60°C oven and heated for 13 hours.

[0079] The above method can be used to obtain a broadband detectable photoelectric sensor.

[0080] Figure 2 This embodiment illustrates the phase analysis of CsPbBr3 deposited on a substrate by varying the magnetic field strength. The figure shows that the magnetic field strength does not affect the crystal phase of CsPbBr3, but the crystallinity increases with increasing magnetic field strength. This excellent crystallinity lays the foundation for its fabrication as a photoelectric sensor.

[0081] Figure 3This is the photocurrent response spectrum of the photoelectric sensor obtained by magnetic focusing transmission pulsed laser deposition under an external magnetic field strength of 310 Gs in this embodiment. Without applying a bias voltage, the generation of photocurrent can be clearly observed under stimulation by 365 nm light sources of different powers.

[0082] Figure 4 This is the photocurrent response spectrum of the photoelectric sensor obtained by magnetic focusing transmission pulsed laser deposition under an external magnetic field strength of 1237 Gs in this embodiment. Without applying a bias voltage, the generation of photocurrent can be clearly observed under stimulation by 450 nm light sources of different powers, indicating that the photoelectric device also has a good response to visible light.

[0083] Figure 5 This is the photocurrent response spectrum of the photoelectric sensor obtained by magnetic focusing transmission pulsed laser deposition under an external magnetic field strength of 710 Gs in this embodiment. Without applying a bias voltage, the generation of photocurrent can be clearly observed under stimulation by 800 nm light sources of different powers, demonstrating the broad spectral detectability of this photoelectric device and achieving effective detection from ultraviolet to visible to near-infrared light.

[0084] Figure 6 This embodiment presents a photoelectric sensor obtained by magnetic focusing transmission pulsed laser deposition under an external magnetic field strength of 310 Gs. The photoelectric signal response is shown before and after one month of stimulation by an external light source at 0V@365nm. Under suitable low-power light source stimulation, the photocurrent signal is even stronger than the initial signal. After one month, the photocurrent signal under high-power light source stimulation still retains 63% of the original electrical signal, indicating that the PDMS film provides good protection for the photoelectric sensor.

[0085] In this embodiment, a photoelectric sensor was deposited using magnetic focusing transmission pulsed laser deposition under an external magnetic field strength of 1545 Gs. The photodetector fabricated using this magnetic field strength achieved a detectivity (D*) of 3.5 × 10⁻⁶ at 450 nm @ 5 V. 10 Jones measured its response rate (R) to be 56.6 mW / cm². 2 .

[0086] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application. Any specific values ​​in all examples shown and discussed herein should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0087] Furthermore, it should be noted that the use of terms such as "first" and "second" is merely for ease of distinction, and unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a broadband photodetector, characterized in that, Includes the following steps: Interdigitated electrodes are fabricated on a conductive substrate; Perovskite quantum dots are deposited between the interdigitated electrodes; A protective layer is coated on the interdigitated electrode on which the perovskite quantum dots are deposited; The method for depositing perovskite quantum dots is magnetically focused transmission pulsed laser deposition, in which the laser is a femtosecond laser; The output power of the femtosecond laser is 10W to 30W; The pulse width of the femtosecond laser is 350 fs to 1 ps; The pulse repetition frequency range of the femtosecond laser is from 1MHz to 50MHz; The pulse energy of the femtosecond laser is 10 μJ to 80 μJ; The magnetically focused transmission pulsed laser deposition method includes: The perovskite quantum dot powder target is placed at a predetermined distance below the conductive substrate. The perovskite quantum dot powder target and the conductive substrate are placed in an energized solenoid and a uniform magnetic field is applied. Femtosecond lasers are focused onto the surface of perovskite quantum dot powder target materials; The magnetic field strength of the uniform magnetic field is between 200 Gs and 2000 Gs.

2. The method for fabricating a broadband photodetector according to claim 1, characterized in that: The conductive substrate is a gold-plated glass sheet with a thickness of 0.3 mm to 1.0 mm and a gold plating layer thickness of 200 nm to 800 nm.

3. The method for fabricating a broadband photodetector according to claim 1, characterized in that: The length of the interdigital electrode is 3 mm to 10 mm, the width is 9 mm to 30 mm, and the filling gap of the interdigital electrode is 20 μm to 80 μm.

4. The method for fabricating a broadband photodetector according to claim 1, characterized in that: The interdigitated electrodes are prepared by laser etching, photolithography, or sputtering deposition.

5. The method for fabricating a broadband photodetector according to claim 1, characterized in that: The perovskite quantum dots are CsPbBr3 quantum dots, CsPbI3 quantum dots, or CsPbCl3 quantum dots.

6. The method for fabricating a broadband photodetector according to claim 1, characterized in that: The protective layer is made of polydimethylsiloxane, epoxy resin, or UV-curable resin, and is applied by spin coating, spraying, or dip coating.

7. The method for fabricating a broadband photodetector according to claim 6, characterized in that: The thickness of the protective layer is 25 μm to 40 μm.

8. A broadband photodetector, characterized in that, It is prepared according to the fabrication method of the broadband photodetector as described in any one of claims 1-7, comprising: Conductive substrate; Interdigitated electrodes are disposed on the conductive substrate; A perovskite quantum dot layer is deposited between the interdigitated electrodes; A protective layer covers the perovskite quantum dot layer and the interdigitated electrodes.

9. The photodetector according to claim 8, characterized in that, The protective layer is made of polydimethylsiloxane, and the perovskite quantum dot layer is made of CsPbBr3 quantum dots.

Images