A DPP-DTT@t-sb photodetector and a preparation method and use thereof

Abstract

The application discloses a DPP-DTT@t-Sb photoelectric detector for realizing high-efficiency photoelectric detection in near-infrared III (NIR-III) by phase transition induced band gap narrowing and a preparation method thereof, and belongs to the field of near-infrared photoelectric detectors. The photoelectric detector comprises a substrate, a semiconductor layer and a metal electrode arranged in sequence from bottom to top. The substrate is a Si / SiO2 substrate. The semiconductor layer is DPP-DTT doped with 10% tetragonal phase Sb (t-Sb) mixture in mass percentage. The t-Sb is tetragonal phase Sb (t-Sb) formed by implementing phase transition engineering on hexagonal phase Sb (h-Sb). The metal electrode is an Au metal electrode. By implementing phase transition engineering on hexagonal phase Sb (h-Sb) to form tetragonal phase Sb (t-Sb), the NIR light absorption and photoelectric detection performance of the photoelectric detector are significantly improved, the light response current gain and sensitivity are enhanced, and excellent high detection degree is realized in the NIR-III region.

Description

Technical Field

[0001] This invention belongs to the field of photodetectors, specifically relating to a DPP-DTT@t-Sb photodetector that achieves high-efficiency photodetection in the NIR-III region through phase transition-induced bandgap narrowing, and its fabrication method. Background Technology

[0002] A photodetector is a sensor that converts light signals into electrical signals. High-performance photodetectors, especially infrared photodetectors, have important applications in optical communication, thermal imaging, medical, military, and environmental monitoring. Based on the detection wavelength, infrared photodetectors can be classified into near-infrared (0.78-3μm) and mid-infrared (3-30μm) photodetectors, with optical communication bands falling within the near-infrared band. Currently, infrared photodetectors based on traditional compound semiconductor materials such as indium gallium arsenide and mercury cadmium telluride face some challenges, making it difficult to meet the growing commercial demands.

[0003] Novel two-dimensional materials (such as graphene, transition metal dichalcogenides (TMDs), and group VA two-dimensional semiconductors) are crucial for fabricating next-generation low-power, miniaturized photodetectors due to their unique structures and photoelectric properties. However, graphene and TMD-based photodetectors are limited in the NIR region by their low photoresponse and narrow detection range. In contrast, group VA two-dimensional semiconductors (such as black phosphorus, antimonene, and arsenene) exhibit unique advantages in detection sensitivity and photoresponse due to their higher carrier mobility, tunable electronic structure, and excellent photoelectric properties. However, the weak light absorption and wide bandgap of group VA two-dimensional semiconductors in the NIR region limit their photodetector applications there, making it difficult to meet the detection requirements of near-infrared light signals, thus significantly restricting their applications in optical communication, medical, military, and environmental monitoring fields. Therefore, developing new group VA two-dimensional semiconductor materials with strong NIR absorption and narrow bandgap is crucial for developing high-performance NIR photodetectors. Phase change engineering can alter the crystal structure of semiconductor materials, thereby adjusting their energy bands, enhancing their NIR light absorption, and improving the detection performance of NIR photodetectors. For example, researchers have controllably transformed gray arsenene nanosheets into semiconducting glassy arsenene nanosheets to modulate the electrical and optical properties of the arsenene nanosheets, significantly improving carrier mobility (Hu, Y. et al. Wet chemistry vitrification and metal-to-semiconductor transition of 2D gray arsenene nanooflakes. Advanced Functional Materials 31, 2106529 (2021).). Therefore, using phase change engineering to control the crystal structure of group VA two-dimensional semiconductor materials to construct NIR photodetectors is of great significance. Summary of the Invention

[0004] Based on the shortcomings of existing VA group two-dimensional semiconductor materials, such as weak near-infrared light absorption and wide bandgap, the purpose of this invention is to provide a high-performance photodetector that achieves efficient photoelectric detection in the near-infrared III region by narrowing the bandgap induced by phase transition.

[0005] This invention is achieved through the following technical solution:

[0006] A DPP-DTT@t-Sb photodetector includes a substrate, an organic nonpolar hybrid photoelectric functional semiconductor layer, and a metal electrode. The substrate is made of Si / SiO2, the semiconductor layer is made of DPP-DTT doped with 1 to 30 wt.% t-Sb, and the metal electrode is made of gold.

[0007] A method for fabricating a DPP-DTT@t-Sb photodetector as described above includes the following steps:

[0008] S1. Modify the surface of a Si / SiO2 substrate with octadecyltrichlorosilane for later use;

[0009] S2. After blending t-Sb in DPP-DTT solution, spin-coating it onto the Si / SiO2 substrate to form an organic-inorganic hybrid optoelectronic functional semiconductor layer;

[0010] S3. Gold elemental is thermally evaporated onto the prepared substrate through a copper grid to form an Au metal electrode, wherein the thickness of the Au source and drain films is 40-60 nm.

[0011] As a preferred embodiment, the method for modifying the surface of the Si / SiO2 substrate is as follows:

[0012] The cleaned Si / SiO2 substrate was placed in a petri dish, dried under vacuum, heated at 80–100°C for 70–80 min, and then cooled to room temperature. Octadecyltrichlorosilane was added to the petri dish, and the substrate was heated at 110–130°C for 130–140 min under vacuum. Finally, the substrate was allowed to cool naturally to room temperature.

[0013] As a preferred embodiment, the method for preparing t-Sb is as follows:

[0014] h-Sb powder was immersed in a cyclohexane solution of n-butyllithium to obtain a lithium intercalation compound. The upper n-butyllithium solution was removed, and the compound was washed with cyclohexane and then sonicated in ethanol to obtain t-Sb.

[0015] As a preferred embodiment, the method for preparing the h-Sb powder is as follows:

[0016] Weigh commercially available powdered Sb, soak it in ethanol, and sonicate it for 12 hours. Then, centrifuge the resulting suspension at 5000 rpm, take the supernatant, and centrifuge it again at 18000 rpm. Collect the precipitate, disperse it in ethanol, and then vacuum dry it to obtain h-Sb.

[0017] As a preferred embodiment, the concentration of the cyclohexane solution of n-butyllithium is 2.0 mol / L.

[0018] As a preferred embodiment, the mass fraction of t-Sb in the DPP-DTT solution is 10%, and the mass concentration of the DPP-DTT solution is 7 mg / mL.

[0019] As a preferred embodiment, the rate of thermal evaporation is: Pressure is 8×10 -4 Pa.

[0020] Application of a DPP-DTT@t-Sb photodetector as described above in NIR-III region detection.

[0021] The aforementioned DPP-DTT is a polypyrrolopyrroledione-thiophene-thiophenothiophene alternating copolymer.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention proposes a photodetector and its fabrication method for achieving high-efficiency photodetection in the NIR-III region through phase transition-induced bandgap narrowing. The key lies in the use of a DPP-DTT semiconductor layer with a doping mass percentage of 10% t-Sb mixture. The phase transition significantly improves the NIR light absorption and photodetection performance of the constructed photodetector.

[0024] 2. Phase transition engineering was performed on h-Sb, which has a wide bandgap and weak light absorption, by embedding lithium atoms, resulting in the formation of t-Sb, which has a narrow bandgap and strong near-infrared light absorption.

[0025] 3. h-Sb undergoes a phase transition to form t-Sb, which is more easily excited by longer wavelength light, resulting in stronger light absorption; and significantly enhanced light absorption capacity, with an extinction coefficient of 10.1 Lg at 1510 nm. -1 cm -1 It is about 13 times higher than h-Sb, and the electronic band structure of t-Sb shows a narrow bandgap of 0.35eV, which meets the requirements of narrow bandgap semiconductors.

[0026] 4. h-Sb undergoes a phase transition to form t-Sb, enabling the t-Sb photodetector to exhibit excellent NIR light detection capability in the 810 to 1510 nm range. As the power density increases, the detectivity value shows a good linear relationship, indicating that the device has good NIR light detection performance.

[0027] 5. This invention transforms h-Sb into t-Sb through a phase transition by embedding lithium atoms. 10 wt.% of t-Sb is then doped into the semiconductor layer. Based on this, a high-efficiency photodetector for NIR-III region photodetection is constructed. It has a narrow bandgap of 0.35 eV and exhibits excellent NIR light absorption in the range of 810 to 1510 nm, which is about 13 times higher than that of h-Sb. This demonstrates the strong potential of t-Sb after phase transition as a nanomaterial for NIR photodetection.

[0028] 6. The photodetector based on t-Sb for high-efficiency photodetection in the NIR-III region achieved a photodetectance D* of 2.81 × 10⁻⁶ at a wavelength of 1510 nm. 14 Jones. Attached Figure Description

[0029] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the DPP-DTT@t-Sb photodetector designed in this invention, which achieves efficient detection in the NIR-III region by narrowing the bandgap induced by phase transition.

[0031] Figure 2 An optical microscope image of the DPP-DTT@t-Sb semiconductor layer;

[0032] Figure 3 A schematic diagram of the photosensitive properties of the DPP-DTT@t-Sb photodetector;

[0033] Figure 4 A schematic diagram of the photoresponsivity of the DPP-DTT@t-Sb photodetector;

[0034] Figure 5 A schematic diagram of the optical detectivity of the DPP-DTT@t-Sb photodetector;

[0035] Figure 6 h-Sb spherical aberration electron microscopy image;

[0036] Figure 7 This is a spherical aberration electron microscope image of t-Sb. Detailed Implementation

[0037] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0038] The raw materials and instruments used in this invention are all commercially available.

[0039] DPP-DTT was purchased from Nanjing Zhiyan Technology Co., Ltd.; n-butyllithium solution was purchased from Sigma; chloroform (99.8%) was purchased from Yonghua Chemical Co., Ltd.; all materials were used directly without further purification. The Si / SiO2 substrate was purchased from Shanghai Tim New Materials Technology Co., Ltd.

[0040] Example 1

[0041] This invention proposes a DPP-DTT@t-Sb photodetector that achieves high-efficiency photodetection in the NIR-III region through phase transition-induced bandgap narrowing, such as... Figure 1As shown, it includes a substrate, a semiconductor layer, and a metal electrode arranged sequentially from bottom to top; the substrate is a Si / SiO2 substrate; the semiconductor layer is a DPP-DTT doped with a 10 wt.% t-Sb mixture; the t-Sb is formed by performing a phase change engineering on h-Sb; and the metal electrode is an Au metal electrode.

[0042] The DPP-DTT@t-Sb photodetector for high-efficiency photodetection in the NIR-III region described in this embodiment operates in the 810-1510nm band.

[0043] The band gap value of t-Sb described in this embodiment is 0.35 eV.

[0044] This embodiment also proposes a method for fabricating a DPP-DTT@t-Sb photodetector that achieves high-efficiency detection in the NIR-III region through phase transition-induced bandgap narrowing, including the following steps:

[0045] Step 1: Use a highly n-doped Si wafer as the substrate and 500nm thermally oxidized SiO2 as the gate dielectric; combine the two to form a Si / SiO2 substrate;

[0046] Step 2: Weigh 100 mg of commercially available powdered Sb, soak it in 5 mL of ethanol, and sonicate it for 12 hours using an ultrasonic cleaner. Centrifuge the resulting suspension at 5000 rpm for 3 minutes, repeating the process 3 times to collect the supernatant. Finally, centrifuge the resulting supernatant at 18000 rpm for 10 minutes, collect the precipitate, and disperse it in ethanol to obtain h-Sb. Dry the obtained h-Sb ethanol solution in a vacuum drying oven to obtain the h-Sb sample.

[0047] Step 3: Immerse 5 mg of dry h-Sb powder in n-butyllithium (2.0 M cyclohexane solution, 2 mL) and place in a glove box for 12 hours to obtain the lithium intercalation compound. After removing the upper n-butyllithium solution, the material is washed three times with cyclohexane and then sonicated in 5 mL of ethanol for 30 minutes to obtain the t-Sb sample.

[0048] Step 4: Mix t-Sb at 10 wt.% uniformly with a 7 mg / mL DPP-DTT solution and spin-coat the mixture onto an OTS-modified Si / SiO2 substrate to form an organic polarless hybrid optoelectronic functional semiconductor layer.

[0049] Step 5: Apply gold (through a copper mesh) 8×10 -4 The Au metal electrode is formed by thermal evaporation onto a prepared substrate using Pa, wherein the Au source and drain films are approximately 50 nm thick.

[0050] The working principle of the DPP-DTT@t-Sb photodetector with high-efficiency photodetection in the NIR-III region obtained in this embodiment is as follows: In a V region similar to darkness... GS Under near-infrared light irradiation, due to the photovoltaic effect, when the energy of photons is absorbed by the photoelectric functional semiconductor layer, a large number of photogenerated excitons are generated, dissociated, and transported along charge transport paths, leading to I... DS The device is now in an "operating" state. To evaluate the performance of the photodetector, a series of key performance indicators are currently used: photosensitivity (P), photoresponsivity (R), and detectivity (D*). To further investigate its photoresponse behavior, monochromatic light at different intensities of 910 nm, 1110 nm, and 1510 nm was applied. The current response of this type of photodetector was also confirmed to increase with increasing light intensity.

[0051] Depend on Figure 1 As shown in the diagram of the DPP-DTT@t-Sb photodetector structure, Si / SiO2 is used as the device substrate, and organic p-type semiconductor DPP-DTT doped with t-Sb is used as the semiconductor layer of the device. After spin-coating the semiconductor material layer on the Si / SiO2 substrate, gold is evaporated to obtain the source and drain.

[0052] Depend on Figure 2 The optical microscope image of the DPP-DTT@t-Sb semiconductor layer shown in this case demonstrates that the film-forming properties of the DPP-DTT@t-Sb semiconductor layer were characterized using an optical microscope. The DPP-DTT@t-Sb semiconductor layer exhibits good film-forming continuity, and t-Sb displays a distinct metallic luster in the thin film.

[0053] Depend on Figure 3 The transfer output characteristic curves of the DPP-DTT@t-Sb photodetector at different wavelengths shown indicate that the DPP-DTT@t-Sb photodetector has a wide spectral response and still exhibits good photoresponse characteristics in the NIR window region, especially in the NIR-III region.

[0054] Depend on Figure 3 The schematic diagram of the photosensitivity of the DPP-DTT@t-Sb photodetector shows that the optical power density at 1510 nm is 1.325 × 10⁻⁶. -3 mW / cm 2 The photosensitivity of the DPP-DTT@t-Sb photodetector under radiation is 120.

[0055] Depend on Figure 4 The schematic diagram of the photoresponsivity of the DPP-DTT@t-Sb photodetector shows that the optical power density at 1510 nm is 1.325 × 10⁻⁶. -3 mW / cm 2The photoresponsivity of the DPP-DTT@t-Sb photodetector under radiation is 2.6 × 10⁻⁶. 5 A / W;

[0056] Depend on Figure 5 The schematic diagram of the optical detectivity of the DPP-DTT@t-Sb photodetector shows that the optical power density at 1510 nm is 1.325 × 10⁻⁶. -3 mW / cm 2 The optical detectivity of the DPP-DTT@t-Sb photodetector under radiation is 2.81 × 10⁻⁶. 14 Jones.

[0057] Depend on Figure 6 The h-Sb spherical aberration electron microscope image shown indicates that Sb has a hexagonal phase structure before lithium intercalation.

[0058] Depend on Figure 7 The t-Sb spherical aberration electron microscope image shown indicates that after lithium intercalation, Sb has a tetragonal phase structure.

[0059] Comparative Example 1

[0060] This comparative example presents a DPP-DTT@h-Sb photodetector, comprising a substrate, a semiconductor layer, and a metal electrode arranged sequentially from bottom to top; the substrate is a Si / SiO2 substrate; the semiconductor layer is DPP-DTT doped with a 10% h-Sb mixture by mass; the h-Sb is obtained by ultrasonication and centrifugation; and the metal electrode is an Au metal electrode.

[0061] The DPP-DTT@h-Sb photodetector described in this comparative example operates in the 300-1000nm wavelength range.

[0062] The band gap value of h-Sb described in this comparative example is 1.14 eV.

[0063] This comparative example also proposes a method for fabricating a DPP-DTT@h-Sb photodetector, including the following steps:

[0064] Step 1: Use a highly n-doped Si wafer as the gate electrode and 500nm thermally oxidized SiO2 as the gate dielectric; combine the two to form a Si / SiO2 substrate;

[0065] Step 2: Modify the surface of the above Si / SiO2 wafer with octadecyltrichlorosilane (OTS);

[0066] Step 3: Weigh 100 mg of commercially available powdered Sb, soak it in 5 mL of ethanol, and sonicate it for 12 hours using an ultrasonic cleaner. Centrifuge the resulting suspension at 5000 rpm for 3 minutes, repeating the process 3 times to collect the supernatant. Finally, centrifuge the resulting supernatant at 18000 rpm for 10 minutes, collect the precipitate, and disperse it in ethanol to obtain h-Sb. Dry the obtained h-Sb ethanol solution in a vacuum drying oven to obtain h-Sb powder.

[0067] Step 4: Using a DPP-DTT solution doped with 1 wt.% h-Sb mixture as a spin-coating material, an organic-inorganic hybrid semiconductor layer is formed on an OTS-modified Si / SiO2 substrate by spin coating.

[0068] Step 5: Apply gold (through a copper mesh) 8×10 -4 The Au metal electrode is formed by thermal evaporation onto a prepared substrate using Pa, wherein the Au source and drain films are approximately 50 nm thick.

[0069] Comparative Example 2

[0070] Similar to Example 1, the difference is that the content of the t-Sb mixture in step (5) of Example 1 is changed to 1 wt.%, while other conditions remain the same. The NIR photodetector based on this material does not have good detection capability in the NIR band.

[0071] Comparative Example 3

[0072] Similar to Example 1, the difference is that the content of the t-Sb mixture in step (5) of Example 1 is changed to 5 wt.%, while other conditions remain the same. The near-infrared photodetector based on this substance does not have good detection capability in the near-infrared band.

[0073] Comparative Example 4

[0074] Similar to Example 1, the difference is that the content of the t-Sb mixture in step (5) of Example 1 is changed to 15 wt.%, while other conditions remain the same. The near-infrared photodetector based on this substance does not have good detection capability in the near-infrared band.

[0075] Comparative Example 5

[0076] Similar to Example 1, the difference is that the content of the t-Sb mixture in step (5) of Example 1 is changed to 20 wt.%, while other conditions remain the same. The near-infrared photodetector based on this substance does not have good detection capability in the near-infrared band.

[0077] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A DPP-DTT@t-Sb photodetector, comprising a substrate, an organic-inorganic hybrid photoelectric functional semiconductor layer, and a metal electrode, characterized in that, The substrate is made of Si / SiO2, the semiconductor layer is made of DPP-DTT doped with 1 to 30 wt.% t-Sb, and the metal electrode is made of gold.

2. A method for fabricating a DPP-DTT@t-Sb photodetector as described in claim 1, characterized in that, Includes the following steps: S1. Modify the surface of a Si / SiO2 substrate with octadecyltrichlorosilane for later use; S2. After blending t-Sb in DPP-DTT solution, spin-coating it onto the Si / SiO2 substrate to form an organic polarless hybrid optoelectronic functional semiconductor layer. S3. Gold elemental is thermally evaporated onto the prepared substrate through a copper grid to form an Au metal electrode, which serves as the source and drain electrode, and the thickness of the Au source and drain electrode films is 40-60 nm.

3. The fabrication method of the DPP-DTT@t-Sb photodetector as described in claim 2, characterized in that, The modification method for the surface of the Si / SiO2 substrate is as follows: The cleaned Si / SiO2 substrate was placed in a petri dish, dried under vacuum, heated at 80–100°C for 70–80 min, and then cooled to room temperature. Octadecyltrichlorosilane was added to the petri dish, and the substrate was heated at 110–130°C for 130–140 min under vacuum. Finally, the substrate was allowed to cool naturally to room temperature.

4. The method for fabricating the DPP-DTT@t-Sb photodetector as described in claim 2, characterized in that, The preparation method of the t-Sb is as follows: h-Sb powder was immersed in a cyclohexane solution of n-butyllithium to obtain a lithium intercalation compound. The upper n-butyllithium solution was removed, and the compound was washed with cyclohexane and then sonicated in ethanol to obtain t-Sb.

5. The method for fabricating the DPP-DTT@t-Sb photodetector as described in claim 4, characterized in that, The preparation method of the h-Sb powder is as follows: Weigh commercially available powdered Sb, soak it in ethanol, and sonicate it for 12 hours. Then, centrifuge the resulting suspension at 5000 rpm, take the supernatant, and centrifuge it again at 18000 rpm. Collect the precipitate, disperse it in ethanol, and then vacuum dry it to obtain h-Sb powder.

6. The method for fabricating the DPP-DTT@t-Sb photodetector as described in claim 4, characterized in that, The concentration of the n-butyllithium cyclohexane solution is 2.0 mol / L.

7. The method for fabricating the DPP-DTT@t-Sb photodetector as described in claim 2, characterized in that, The mass fraction of t-Sb in the DPP-DTT solution is 10%, and the mass concentration of the DPP-DTT solution is 7 mg / mL.

8. The method for fabricating the DPP-DTT@t-Sb photodetector as described in claim 2, characterized in that, The rate of thermal evaporation is Pressure is 8×10 -4 Pa.

9. The use of the DPP-DTT@t-Sb photodetector as described in claim 1 in NIR-III region photodetection.

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