Te-based photoelectric detector based on Te metasurface homogeneous integration and preparation method thereof

Abstract

The invention belongs to the technical field of micro-nano optics and photoelectric detection, and particularly discloses a Te-based photoelectric detector based on Te metasurface homogeneous integration and a preparation method thereof, and the Te-based photoelectric detector comprises a substrate, a Te film photoelectric sensing layer, a metal source electrode, a metal drain electrode and a Te metasurface layer as a local light processing layer. According to the Te metasurface homogeneous integration-based Te-based photoelectric detector, the absorptivity of the Te thin film light sensing layer to the C wave band is increased by the Te metasurface, the photoelectric detection performance of the constructed Te-based photoelectric detector based on Te metasurface homogeneous integration can be remarkably improved, and the problems that the absorptivity is low and the photoelectric performance is reduced due to the fact that the thickness is reduced in order to reduce dark current of a traditional Te thin film photoelectric detector are solved.

Description

Technical Field

[0001] This invention relates to the fields of micro-nano optics and photoelectric detection technology, and in particular to a Te-based photodetector based on Te metasurface homogeneous integration and its fabrication method. Background Technology

[0002] Photodetectors, as core devices for converting optical signals into electrical signals, have important applications in optical communication, optical imaging, and optical sensing. Tellurium (Te), as a narrow bandgap semiconductor (approximately 0.35 eV), possesses broad spectral response characteristics, covering a wide spectral range from visible light to infrared. Furthermore, Te exhibits extremely high hole mobility (up to approximately 700 cm⁻¹ at room temperature). 2 The Te bandgap ( / V·s) facilitates the rapid transport and collection of photogenerated carriers, providing a material basis for constructing high-speed response photodetectors. However, its narrow bandgap also results in high intrinsic conductivity in Te films, making Te materials generally face the challenge of high dark current in practical applications. Although reducing the Te thickness can suppress dark current to some extent, it significantly reduces the material's light absorption efficiency, thus limiting the optimization of the overall performance of photodetector devices.

[0003] Currently, published research mainly addresses the challenge of balancing high dark current and low absorbance in Te-based detectors by constructing same-dimensional or mixed-dimensional heterojunction structures. Examples include Chinese Patent Application No. 202510998900.8, which discloses a tellurium / germanium heterojunction photodetector and its fabrication method using low-temperature thermal evaporation deposition, and Chinese Patent Application No. 202411375463.6, which discloses a tellurium-based oxide-based heterojunction self-powered infrared photodetector and its fabrication method. However, these methods generally face challenges such as high process complexity and significant lattice mismatch at the heterojunction interface, which exacerbates the scattering and recombination of photogenerated carriers, limiting further improvements in device performance. Furthermore, while reducing dark current, heterojunction devices experience a significant decrease in responsivity, necessitating complex amplification circuits for matching during subsequent integration, hindering the development of miniaturized devices. Therefore, maintaining high absorbance while reducing low dark current in Te-based photodetectors remains a critical technical challenge that urgently needs to be overcome in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a Te-based photodetector based on homogeneous integration of a Te metasurface and its fabrication method. The homogeneous structure design avoids interface defects caused by lattice mismatch. At the same time, the Mie resonance generated by the strong coupling between the Te metasurface and the Te thin film enhances infrared light absorption. While suppressing dark current, it can maintain excellent light absorption and carrier transport characteristics, providing a new technical path for high-performance, easily integrated Te-based photodetectors.

[0005] To achieve the above objectives, the present invention is implemented according to the following technical solution: The first technical solution provided by this invention is a Te-based photodetector based on homogeneous integration of a Te metasurface, comprising a substrate; a Te thin-film photosensitive layer is disposed on the upper surface of the substrate; a metal source electrode is disposed on one side of the upper surface of the Te thin-film photosensitive layer; a metal drain electrode is disposed on the other side of the upper surface of the Te thin-film photosensitive layer; and a Te metasurface layer serving as a localized light processing layer is disposed on the upper surface of the Te thin-film photosensitive layer between the metal source electrode and the metal drain electrode. When light is incident from the top of the metasurface layer, it propagates along the Z-axis direction, and the light coupled after passing through the Te metasurface is localized on the Te thin film, increasing the absorption rate of the Te metasurface.

[0006] Furthermore, the Te metasurface layer is composed of multiple micro-nano structures, the cross-section of which is one of circular, rectangular, square, and elliptical.

[0007] Furthermore, the substrate material is one of Si / SiO2, quartz, sapphire, PI, and PET.

[0008] Furthermore, the thickness of the Te thin film photosensitive layer is 5-80 nm.

[0009] Furthermore, the materials of the metal drain electrode and the metal source electrode are one or a combination of Cr, Ti, Ag and Au, and the thickness of the metal drain electrode and the metal source electrode is 30-50 nm.

[0010] Furthermore, the cross-section of the micro / nano structure is circular with a diameter of 160-300 nm, and the height of the micro / nano structure is 150 nm-300 nm.

[0011] Furthermore, the cross-section of the micro / nano structure is rectangular, with a long side length of 200nm-300nm and a short side length of 100nm-150nm. The height of the micro / nano structure is 150nm-300nm.

[0012] Furthermore, the cross-section of the micro / nano structure is square with a side length of 100nm-300nm, and the height of the micro / nano structure is 150nm-300nm.

[0013] Furthermore, the cross-section of the micro / nano structure is elliptical, with a major axis of 200nm-300nm and a minor axis of 100nm-150nm, and the height of the micro / nano structure is 150nm-300nm.

[0014] The second technical solution provided by this invention is a method for fabricating a Te-based photodetector based on homogeneous integration of Te metasurfaces, comprising the following steps: S1. Deposit a Te thin film on the upper surface of a clean substrate to form a Te thin film photosensitive layer; S2. Deposit metal source electrodes and metal drain electrodes on both sides of the upper end face of the Te thin film photosensitive layer; S3. A Te metasurface layer is deposited on the upper surface of the Te thin film photosensitive layer between the metal source electrode and the metal drain electrode to obtain a Te-based photodetector based on the homogeneous integration of the Te metasurface.

[0015] Compared with existing technologies, this invention increases the absorption rate of the Te thin film photosensitive layer to the C-band by using a Te metasurface. The Te-based photodetector constructed based on the homogeneous integration of the Te metasurface can significantly improve photoelectric detection performance. It solves the problems of low absorption rate and decreased photoelectric performance caused by reducing thickness to reduce dark current in traditional Te thin film photodetectors. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of an exemplary Te-based photodetector based on Te metasurface homogeneous integration.

[0017] Figure 2 This is a diagram illustrating the fabrication process of an exemplary Te-based photodetector based on Te metasurface homogeneous integration.

[0018] Figure 3 This is a schematic diagram of the simulated absorption rate of the Te metasurface.

[0019] Figure 4 This is a schematic diagram of the simulated electric field for a Te metasurface homogeneously integrated on a Te thin film.

[0020] Figure 5 The net photocurrent response curves of Te thin film and Te thin film of homogeneous integrated Te metasurface at a wavelength of 1550 nm with a bias voltage of 1 V are shown. The net photocurrent is the illumination current I. ph Subtract dark state current I dark .

[0021] In the figure, the reference numerals are: 100 - substrate; 101 - Te thin film photosensitive layer; 102 - metal source electrode; 103 - metal drain electrode; 104 - Te metasurface layer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0023] like Figure 1As shown in the figure, this embodiment exemplarily demonstrates a Te-based photodetector based on Te metasurface homogeneous integration, including a substrate 100, which in this embodiment is exemplarily selected as a Si / SiO2 substrate; a Te thin film photosensitive layer 101 with a thickness of 80 nm is provided on the upper surface of the substrate 100; a metal source electrode 102 with a thickness of 40 nm is provided on one side of the upper surface of the Te thin film photosensitive layer 101, which is exemplarily made of Au material; a metal drain electrode 103 is provided on the other side of the upper surface of the Te thin film photosensitive layer 101, which is also made of Au material; a Te metasurface layer 104 as a local light processing layer is provided on the upper surface of the Te thin film photosensitive layer 101 between the metal source electrode 102 and the metal drain electrode 103. The Te metasurface layer 104 is composed of multiple micro-nano structures, the cross-section of which is circular, i.e., the micro-nano structure is cylindrical, with a diameter of 200 nm and a height of 200 nm. The periodic structure of the metasurface unit structure is rectangular, with a long side length of 1. µm, with a short side length of 740 nm and an array period of 90*110.

[0024] exist Figure 1 Based on, refer to Figure 2 This embodiment exemplifies a method for fabricating a Te thin-film photodetector with a homogeneous integrated Te metasurface operating at a wavelength of 1550 nm. The design steps of the specific embodiment are as follows: Step 1: The Si / SiO2 substrate is cleaned sequentially with acetone, isopropanol, and deionized water, and then thoroughly cleaned with high-purity nitrogen.

[0025] Step 2: The Te thin film deposition area is exposed on the Si / SiO2 substrate using photolithography, and then developed to obtain the area to be deposited. The Te thin film is deposited by thermal evaporation, with the evaporation rate controlled at 0.2 Å / s and the deposition thickness at 80 nm, forming the Te thin film photosensitive layer 101.

[0026] Step 3: Pattern the source and drain electrode regions on the Te thin film photosensitive layer 101 using photolithography. Then, deposit metal on both sides of the photosensitive layer of the Te thin film 101 using electron beam evaporation or thermal evaporation to form metal source electrode 102 and metal drain electrode 103 with a thickness of 40 nm.

[0027] Step 4: Expose the Te metasurface pattern on the upper surface of the Te thin film photosensitive layer 101 between the metal source electrode 102 and the metal drain electrode 103 using electron beam lithography. First, perform a homogenization process on the Si / SiO2 substrate with the deposited Te thin film photosensitive layer 101. Liquid adhesion promoter is dropped onto the center of the Si / SiO2 substrate 100, and the rotation speed is controlled (4000 rpm for 60 seconds), followed by baking at 100°C for 1 minute. Then, liquid photoresist is dropped onto the center of the Si / SiO2 substrate 100, and the rotation speed is controlled (2000 rpm for 60 seconds), followed by baking at 150°C for 3 minutes. Furthermore, a Te metasurface layer 104 was patterned on the Te thin-film photosensitive layer 101 using electron beam lithography. The micro / nano structure of the Te metasurface layer 104 is cylindrical with a diameter of 200 nm and a height of 200 nm. The periodic structure of the metasurface unit structure is rectangular with a long side length of 1 µm and a short side length of 740 nm, and an array period of 90*110. The electron beam lithography system had a voltage of 30 kV, a beam current of 10 pA, and a field of view of 100 µm. After exposure, development was performed for 50 s, and fixing for 20 s, resulting in the patterned area of ​​the Te metasurface 104. Subsequently, the Te metasurface cylinder was deposited by thermal evaporation, controlling the deposition rate at 0.2 Å / s to achieve a deposition thickness of 200 nm. The sample was then immersed in N-methylpyrrolidone for 12 hours to remove the photoresist, resulting in a Te thin-film photodetector device with homogeneous integrated Te metasurface layer 104.

[0028] Furthermore, optical simulations were performed on the designed Te metasurface, referencing... Figure 3 It can be seen that the absorption rate of a pure 80nm Te film at 1550 nm is 9%, while the absorption rate of the Te metasurface is 51%, an increase of 42%. (Reference) Figure 4 As can be seen from the XZ cross-sectional diagram, when a 1550 nm laser is incident from the Z-axis, the electric field energy is localized at the bottom of the Te metasurface layer 104 and the center of the Te thin film photosensitive layer 101. This verifies that adding the Te metasurface layer 104 can increase the light absorption rate of the Te thin film. The simulation data above show that the absorption resonance peak at 1550 nm is obtained after designing the Te metasurface layer in the Te thin film photosensitive layer 101, resulting in a significant enhancement of the Te thin film's absorption rate.

[0029] Further, refer to Figure 5Photoelectric testing was performed on the Te thin film photosensitive layer 101 prepared in step one. A 1550 nm wavelength laser was aimed at the Te thin film photosensitive layer 101 for IT testing, and the bias voltage was set to 1V. The net photocurrent of the Te thin film photosensitive layer 101 was found to be 0.24 µA. On the other hand, photoelectric testing was performed on the Te thin film device with the homogeneous integrated Te metasurface prepared in step four. A 1550 nm wavelength laser was aimed at the Te metasurface for IT testing, and the bias voltage was set to 1V. The net photocurrent of the Te metasurface was found to be 0.66 µA, which is nearly 3 times higher than the previous result.

[0030] In summary, the Te-based photodetector design and fabrication method based on homogeneous integration of Te metasurfaces proposed in this invention allows for the direct fabrication of the core Te metasurface structure using mature thermal evaporation and patterning processes. The device structure is simple and highly integrated, eliminating the need for complex heterostructures. Crucially, the homogeneous integrated Te metasurface device constructed in this invention maintains excellent infrared absorption and 1550 nm infrared response characteristics while suppressing dark current. Infrared absorption is significantly enhanced through the Mie resonance effect between the Te metasurface and the Te thin film. Simultaneously, the homogeneous structure avoids carrier scattering and recombination caused by interfacial lattice mismatch. This achieves low dark current and high responsivity photodetection without significantly reducing the Te thickness, providing a feasible technical path for high-performance, easily integrated Te-based photodetectors.

[0031] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A Te-based photodetector based on Te metasurface homogeneous integration, comprising a substrate; characterized in that: The substrate has a Te thin film photosensitive layer on its upper surface; a metal source electrode is provided on one side of the upper surface of the Te thin film photosensitive layer; a metal drain electrode is provided on the other side of the upper surface of the Te thin film photosensitive layer; and a Te metasurface layer serving as a local light processing layer is provided on the upper surface of the Te thin film photosensitive layer between the metal source electrode and the metal drain electrode.

2. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 1, characterized in that: The Te metasurface layer is composed of multiple micro-nano structures, and the cross-section of the micro-nano structures is one of the following: circular, rectangular, square, and elliptical.

3. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 1, characterized in that: The substrate material is one of Si / SiO2, quartz, sapphire, PI, and PET.

4. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 1, characterized in that: The thickness of the Te thin film photosensitive layer is 5-80 nm.

5. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 1, characterized in that: The materials of the metal drain electrode and the metal source electrode are one or a combination of Cr, Ti, Ag and Au, and the thickness of the metal drain electrode and the metal source electrode is 30-50 nm.

6. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 2, characterized in that: The cross-section of the micro / nano structure is circular with a diameter of 160-300 nm, and the height of the micro / nano structure is 150 nm-300 nm.

7. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 2, characterized in that: The cross-section of the micro-nano structure is rectangular, with a long side length of 200nm-300nm and a short side length of 100nm-150nm. The height of the micro-nano structure is 150nm-300nm.

8. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 2, characterized in that: The cross-section of the micro / nano structure is square with a side length of 100nm-300nm, and the height of the micro / nano structure is 150nm-300nm.

9. The Te-based photodetector based on Te metasurface homogeneous integration according to claim 2, characterized in that: The cross-section of the micro / nano structure is elliptical, with a major axis of 200nm-300nm and a minor axis of 100nm-150nm. The height of the micro / nano structure is 150nm-300nm.

10. A method for fabricating a Te-based photodetector based on homogeneous integration of a Te metasurface as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Deposit a Te thin film on the upper surface of a clean substrate to form a Te thin film photosensitive layer; S2. Deposit metal source electrodes and metal drain electrodes on both sides of the upper end face of the Te thin film photosensitive layer; S3. A Te metasurface layer is deposited on the upper surface of the Te thin film photosensitive layer between the metal source electrode and the metal drain electrode to obtain a Te-based photodetector based on the homogeneous integration of the Te metasurface.

Images