A nonlinear upconversion photodetector and a preparation method thereof
By constructing a MoS2/BaTiO3 heterostructure in a photodetector and utilizing the ferroelectric properties of BaTiO3 to modulate the Fermi level of MoS2, nonlinear upconversion is achieved, solving the strong light blinding effect, broadening the response bandwidth, and improving the reliability and integration of the device.
Patent Information
- Application Number
- CN202410714660.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-04
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2044-06-04
AI Technical Summary
Existing photodetectors are prone to blinding effects under strong light, leading to image distortion and overcurrent problems, and their device structure is not conducive to highly compact integration.
A Cr/Au cross electrode was fabricated on a transparent quartz substrate, and a MoS2 thin layer was transferred onto it. Then, an aqueous solution of BaTiO3 was spin-coated to construct a MoS2/BaTiO3 heterostructure. The ferroelectric properties of BaTiO3 were used to adjust the Fermi level of MoS2 to achieve nonlinear upconversion detection.
Achieving nonlinear upconversion under strong light irradiation broadens the response bandwidth, ensuring reliable operation under high-intensity light conditions and improving the reliability and integration of the photodetector.
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Figure CN118738154B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a photoelectric detector, in particular to a nonlinear up-conversion photoelectric detector and a preparation method thereof, and belongs to the technical field of photoelectric detectors. BACKGROUND
[0002] Photoelectric detectors are crucial in various technical fields such as optical communication, optical imaging systems, medical diagnosis and environmental monitoring. At present, most researchers pursue high-performance photoelectric conversion efficiency through material optimization and device architecture design, but few researchers pay attention to the reliability of devices under extreme working conditions, such as strong light irradiation. For ordinary photoelectric detectors, in principle, under weak light, the photon energy is absorbed by the semiconductor through band transition, effectively converting into current, and the interference is small. Generally, high photoelectric conversion efficiency can be achieved under such conditions. However, the absorption of the semiconductor is usually limited, and it is easy to reach saturation absorption under strong light irradiation. Therefore, it is difficult to obtain contrast differences in imaging applications, and image distortion will occur, which is also known as the blinding effect of photoelectric detectors. In addition, strong light will cause serious thermal effects and additional overcurrent problems, thereby accelerating the degradation and damage of the detector. Generally, people can weaken the strong light blinding effect by physically attenuating the incident strong light or increasing the automatic gain control circuit in the back end. However, the bulky device structure is not conducive to high compact integration.
[0003] Therefore, a nonlinear up-conversion photoelectric detector and a preparation method thereof are designed to solve the above problems. SUMMARY
[0004] The purpose of the present application is to provide a nonlinear up-conversion photoelectric detector for solving the strong light blinding effect, so as to solve the problem that the existing photoelectric detector cannot use its own working mechanism to solve the strong light blinding effect.
[0005] Technical scheme: the nonlinear up-conversion photoelectric detector for solving the strong light blinding effect comprises a transparent quartz substrate, a Cr / Au cross electrode prepared on the quartz substrate, a MoS2 thin layer transferred on the cross electrode, and a BaTiO3 aqueous solution spin-coated on the MoS2 thin layer.
[0006] The nonlinear up-conversion photoelectric detector for solving the strong light blinding effect comprises a transparent quartz substrate, a Cr / Au cross electrode prepared on the quartz substrate, a MoS2 thin layer transferred on the cross electrode, and a BaTiO3 aqueous solution spin-coated on the MoS2 thin layer.
[0007] Further, the heterostructure is constructed by a low-cost peeling and transferring method combined with a spin-coating technology, so as to realize the complementary of the high conductivity of the MoS2 thin layer and the ferroelectric performance of the BaTiO3 thin layer.
[0008] Further, the polarization strength of ferroelectric BaTiO3 is very sensitive to electric field and laser irradiation, and BaTiO3 can provide a local ferroelectric field on the MoS2 channel, thereby effectively adjusting the Fermi level height of MoS2, thereby changing its conductivity, and finally converting the external field stimulation into current enhancement.
[0009] Further, under strong laser irradiation, the device will introduce SHG effect to realize nonlinear upconversion detection, solving the strong light blinding effect.
[0010] Further, the MoS2 / BaTiO3 device maintains significant photoresponse to near-infrared stimulation, and under strong power light irradiation (593 mW), the net photocurrent can reach 1.33 μA at a bias voltage of 0.15 V.
[0011] Further, unlike the traditional photoconductive effect, the 1064 nm laser interacts with the ferroelectric BaTiO3 thin layer, and based on the second harmonic generation (SHG) effect, it can be upconverted to 532 nm light emission, which is then absorbed by the underlying MoS2 thin layer to form a photocurrent.
[0012] Further, under 0 V bias, the device has no obvious response to weak light, but when the incident power is greater than 0.01 W, the response slope of the device increases sharply to 1.99, indicating that the device has a second-order nonlinear conversion mechanism.
[0013] Further, as the incident light power increases from weak to strong, the photoresponse of the photodetector first decreases and then increases, and the monotonically increasing part is mainly contributed by the nonlinear upconversion mechanism.
[0014] Further, using nonlinear upconversion technology can realize detection in the near-infrared range, which can widen the response bandwidth and meet the reliable operation requirements under high-intensity light irradiation.
[0015] Further, the preparation steps of the nonlinear upconversion photodetector for solving the strong light blinding effect are as follows:
[0016] (1) Use standard photolithography process to determine the electrode pattern, then deposit Gr layer (15 nm) and Au layer (45 nm) on the quartz substrate in sequence to form the electrical contact electrode.
[0017] (2) Use mechanical exfoliation to exfoliate a MoS2 thin layer from a commercial bulk single crystal, and use transfer technology to precisely assemble the original MoS2 device under a microscope.
[0018] (3) Place the original MoS2 device on a spin coater and spin coat BaTiO3 aqueous solution to obtain the photodetector.
[0019] The beneficial technical effects of the present application are as follows:
[0020] The present application provides a kind of nonlinear up-conversion photoelectric detector and preparation method thereof, based on the nonlinear up-conversion photoelectric detector obtained in the present application, near-infrared detection can be realized by nonlinear up-conversion, the widening of response band range is realized, and the requirement of reliable operation under strong light irradiation is met. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 It is the schematic diagram of the detector device structure and principle of the present application.
[0022] Figure 2 It is the principle diagram of photoelectric detector under 1064nm picosecond laser irradiation in the embodiment of the present application.
[0023] Figure 3 It is the I-V curve schematic diagram of photoelectric detector under 1064nm laser irradiation under different power densities in the embodiment of the present application.
[0024] Figure 4 It is the power-dependent photocurrent schematic diagram of photoelectric detector extracted under different bias voltages in the embodiment of the present application.
[0025] Figure 5 It is the power-dependent photoresponsivity schematic diagram of photoelectric detector calculated under different bias voltages in the embodiment of the present application.
[0026] Figure 6 It is the SHG spectrum of photoelectric detector under different incident FW powers in the embodiment of the present application.
[0027] Figure 7 It is the relationship schematic diagram of FW power and SHG power calculated according to photoelectric detector in the embodiment of the present application.
[0028] In the figure, 1-quartz substrate;
[0029] 2-Cr / Au cross electrode;
[0030] 3-MoS2 thin layer;
[0031] 4-BaTiO3 thin layer;
[0032] 5-infrared incident light;
[0033] 6-visible light converted by BaTiO3 nonlinear;
[0034] 7-photocurrent. DETAILED DESCRIPTION
[0035] In order to make the technical solution of the present application more clear and explicit to those skilled in the art, the present application will be further described in detail below in conjunction with examples and drawings, but the embodiments of the present application are not limited thereto.
[0036] The transparent quartz substrate 1 is included, Cr / Au cross electrodes 2 are prepared on the quartz substrate, the transfer of the MoS2 thin layer 3 is realized on the cross electrodes, and the BaTiO3 thin layer 4 is spin-coated on the MoS2 thin layer 3;
[0037] The heterostructure is constructed by combining the low-cost peeling and transfer method with the spin-coating technology, the high conductivity of the MoS2 thin layer 3 and the ferroelectric performance of the BaTiO3 thin layer 4 are complementary.
[0038] The polarization intensity of the ferroelectric BaTiO3 is very sensitive to the electric field and laser irradiation, and the BaTiO3 can provide a local ferroelectric field on the MoS2 channel, thereby effectively adjusting the Fermi level height of the MoS2, changing its conductivity, and finally converting the external field stimulation into current enhancement.
[0039] Further, under the irradiation of the infrared incident light 5, the device will introduce the SHG effect to realize nonlinear up-conversion detection, and solve the strong light-induced blindness effect.
[0040] Further, the MoS2 / BaTiO3 device maintains significant photoresponse to near-infrared stimulation, and under strong power light irradiation (593 mW), the net photocurrent can reach 1.33 μA under a bias voltage of 0.15 V.
[0041] Further, unlike the traditional photoconductive effect, the 1064 nm laser interacts with the ferroelectric BaTiO3 thin layer, and based on the second harmonic generation (SHG) effect, it can be up-converted to 532 nm light emission, which is then absorbed by the underlying MoS2 thin layer to form a photocurrent.
[0042] Further, under a bias voltage of 0 V, the response of the device under weak light is not obvious, but when the incident power is greater than 0.01 W, the response slope of the device increases sharply to 1.99, indicating that the device has a second-order nonlinear conversion mechanism.
[0043] Further, as the incident light power continuously increases from weak to strong, the photoresponsivity of the photodetector first decreases and then increases, and the monotonically increasing part is mainly contributed by the nonlinear up-conversion mechanism.
[0044] Further, using the nonlinear up-conversion technology can realize detection in the near-infrared range, which can widen the response bandwidth and at the same time meet the reliable operation demand under high-intensity light irradiation.
[0045] Further, the preparation steps of the nonlinear up-conversion photodetector for solving the strong light-induced blindness effect are as follows
[0046] (1) The electrode pattern is determined by using a standard photolithography process, and then a Gr layer (15 nm) and an Au layer (45 nm) are sequentially deposited on a quartz substrate to form an electrical contact electrode.
[0047] (2) A MoS2 thin layer 3 is peeled off from a commercial bulk single crystal by using mechanical peeling, and a primitive MoS2 device is obtained by precise assembly under a microscope using a transfer technique.
[0048] (3) The primitive MoS2 device is placed on a spin coater, and a BaTiO3 aqueous solution is used for spin coating to obtain a photoelectric detection device.
[0049] Example 1
[0050] The strong light blinding effect of a photoelectric detector refers to the phenomenon that the performance of the photoelectric detector is affected or even temporarily disabled when the photoelectric detector is irradiated by strong light. This phenomenon is usually caused by the overload of photoelectrons or the accumulation of charges caused by strong light, which exceeds the processing capacity of the detector, resulting in abnormal output signal or temporary failure of the detector. The strong light blinding effect is an important consideration for some high-sensitivity photoelectric detectors, especially in environments with large changes in light intensity. In order to alleviate this effect, the present application designs a nonlinear upconversion photoelectric detector that can be used to solve the strong light blinding effect.
[0051] Figure 1 The device structure and principle of the present application are shown in the figure, and the high-conductivity MoS2 can make up for the insufficient charge transport of the original BaTiO3, and the ferroelectric BaTiO3 is beneficial to expand the detection band of the original MoS2, so that the heterostructure device has been significantly improved in the light response in the visible and near-infrared bands.
[0052] The MoS2 / BaTiO3 device optimized by the present application obtains a high light response rate of 17402 a / W under 0.2 nW irradiation, can generate a high photocurrent of 570 μA under 8 mW irradiation, and the linear dynamic range (LDR) index reaches 152 dB, which is at the highest level in layered semiconductor detectors.
[0053] In addition, when the infrared light of sufficient power to cause the strong light blinding effect of ordinary photoelectric detectors is incident on the photoelectric detector device of the present application, the asymmetric junction of the ferroelectric material BaTiO3 has excellent nonlinear effect, as shown in the figure. Figure 2
[0054] The photoelectric detection device of the present application can convert 1064 nm infrared light into 532 nm visible light through the ferroelectricity of BaTiO3 when the BaTiO3 is irradiated by 1064 nm picosecond laser, and then the visible light is absorbed by the MoS2 layer at the bottom to form a transmittable photocurrent, realizing the conversion mechanism of infrared incident light to visible light, thereby solving the strong light blinding effect.
[0055] Therefore, although the 1064 nm picosecond laser is far from the light absorption band edge of BaTiO3 and MoS2, the MoS2 / BaTiO3 heterojunction device still maintains significant photoresponse to near-infrared stimulation, as shown in Figure 3 The net photocurrent of the photoelectric detector can reach 1.33 μA under strong power light irradiation (593 mW) and 0.15 V voltage bias.
[0056] In Figure 4 , the reason for the excellent response of the photoelectric detector to near-infrared light is disclosed.
[0057] Under 0 V bias, the response of the device to weak light is not obvious, but when the incident power is greater than 0.01 W, the response slope of the device increases sharply by about 1.99 times, which indicates that the device prepared by the present application has an excellent second-order nonlinear conversion mechanism.
[0058] This is different from the traditional photoconductive effect, and when the 1064 nm wavelength laser interacts with the ferroelectric BaTiO3, it is converted to 532 nm wavelength based on the second harmonic generation (SHG) effect, and is absorbed by the bottom MoS2 to form a photocurrent. In addition, the polarization direction can be adjusted in the presence of a bias voltage to affect the nonlinear conversion efficiency, and the slope is less than about 2.
[0059] Generally, when evaluating the ability of a common photoelectric detector to convert incident light into electricity, the "photoresponsivity" index is used. This index performs best under weak incident power conditions and decreases monotonically with increasing incident power. This is because the number of non-equilibrium carriers is huge under high incident power conditions and the mutual scattering phenomenon is prominent, which leads to energy dissipation through other channels, thereby reducing the internal quantum efficiency. It is worth mentioning that researchers are currently working on developing various strategies to optimize devices to achieve high sensitivity detection of weak signals, but few people pay attention to whether the operating characteristics are stable and reliable under high incident power conditions.
[0060] Figure 5The MoS2 / BaTiO3 heterojunction device shows another attractive point: the power-dependent photoresponse of the photodetector decreases first and then increases with the continuous increase of the input power; the monotonous increasing part is mainly contributed by the second-order nonlinear upconversion mechanism; in addition, the direct acquisition of the spectrum and the capture of the position of the excitation point after frequency doubling also confirm the existence of the SHG process, as shown in Figure 6 and Figure 7 The above results show that the second-order nonlinear upconversion mechanism can be used to realize the near-infrared region detection function and widen the effective working range to meet the demand of high output signal.
[0061] According to the experimental results of the embodiments, the nonlinear upconversion photodetector prepared by the application can introduce the SHG effect and realize nonlinear upconversion detection under strong laser irradiation. The photodetector has high photoresponse performance and wide linear dynamic range, and is a kind of excellent detector.
[0062] The above description is only further embodiments of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can make equivalent replacement or change according to the technical solutions and concepts of the application within the scope disclosed by the application, which shall also belong to the protection scope of the application.
Claims
1. A nonlinear upconverting photodetector, characterized by: The application relates to a transparent quartz substrate (1), Cr / Au cross electrodes (2) are arranged on the top of the quartz substrate (1); A MoS2 thin layer (3) is arranged on the quartz substrate (1) and between the two groups of Cr / Au cross electrodes (2); A BaTiO3 thin layer (4) is spin-coated on the MoS2 thin layer (3).
2. The method of claim 1, based on the nonlinear upconversion photodetector of claim 1, wherein: The application further discloses a preparation method of the MoS2 photoelectric detector. Step one: electrode patterns are determined by using a standard photoetching process, then a Gr layer and an Au layer are sequentially deposited on the quartz substrate (1) to form an electrical contact electrode; Step two: a MoS2 thin layer (2) is peeled off from a commercial bulk single crystal by using mechanical peeling, and the original MoS2 device is precisely assembled with the electrode under a microscope by using a transfer technology; Step three: the original MoS2 device is placed on a spin coater, and a BaTiO3 aqueous solution is used for spin coating to obtain a photoelectric detection device.
3. The method of claim 2, wherein the method further comprises: The thickness of the Gr layer is 15 nm, and the thickness of the Au layer is 45 nm.