Semiconductor photoelectric device suitable for ultraviolet index monitoring and application method thereof

Abstract

The invention provides a semiconductor photoelectric device suitable for ultraviolet index monitoring, which can extract an ultraviolet band signal under a solar spectrum, and the response characteristic of the semiconductor photoelectric device is enhanced along with time. According to the invention, ultraviolet intensity detection under a composite spectrum can be realized without the help of a reflection increasing film technology or combination of an optical filter when an ultraviolet band optical signal is detected; in a word, the semiconductor photoelectric detection device provided by the invention can detect the ultraviolet index under the solar spectrum without being influenced by a non-ultraviolet band while realizing visible light detection, and the specificity related to action time enables the light signal interference of the visible light band to be ignored in long-time detection; in addition, the relation between the detection signal intensity and the ultraviolet wavelength accords with the correlation between the damage coefficient and the ultraviolet wavelength proposed by the international standard organization, which shows that the device has a certain application value in the ultraviolet damage detection under the sunlight.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic detection engineering technology, and particularly relates to a semiconductor optoelectronic device suitable for ultraviolet index monitoring and an application method thereof. Background Art

[0002] In the field of ultraviolet detection, the detection and monitoring of the intensity or dose of non-visible ultraviolet rays in the short-wave, medium-wave, and long-wave bands of 100nm - 280nm, 280nm - 315nm, and 315nm - 400nm respectively have important significance in the fields of environmental detection, health protection, safety detection, surface physical and chemical detection, industrial manufacturing, and military reconnaissance. In terms of health protection, although the ultraviolet rays irradiating the skin epidermis can be used for sterilization due to their high energy, when the skin absorbs excessive ultraviolet rays, it will cause damage such as sunburn erythema or melanin deposition. Some studies have shown that ultraviolet rays even have the risk of carcinogenesis due to their strong ability to damage DNA. It should be noted that due to the strong reflection of ultraviolet light by the atmosphere, the ultraviolet rays reaching the earth's surface are concentrated in the UVB band of 280 - 315nm and the UVA band of 315 - 400nm, and the damage characteristics of these two types of ultraviolet rays to the skin are different. Figure 1 The shown ultraviolet damage schematic diagram shows that 70% of UVB is absorbed by the stratum corneum, 20% reaches the viable epidermis, and only 10% penetrates to the uppermost part of the dermis, while part of UVA is absorbed by the epidermis, and 20% - 30% can reach the deep part of the dermis. This results in that the irradiation damage of UVB is easy to cause skin aging, while the irradiation damage of UVA is easy to cause skin redness, sunburn or peeling. Therefore, the detection of the intensity of ultraviolet rays reaching the earth's surface is of great significance for health protection.

[0003] However, limited by the physical properties of photosensitive materials, the wavelength-related response characteristics of some ultraviolet detection devices can still be improved in specific applications. In addition, some devices are large in size, making them not easy to be portable or realize wearable applications for ultraviolet safety detection. Although the Si-based process is mature, conventional Si photodetectors have a strong response to visible light and a weak response to the ultraviolet band, and need ultraviolet band enhancement processes (such as adding ultraviolet antireflection films) or using them in combination with filters. Currently, industrialized ultraviolet detection devices are mainly based on third-generation semiconductors such as SiC, GaN, or Ga2O3. Although the influence of the visible light band and the use of filters are avoided, there is still room for improvement in their response characteristics for specific application scenarios.

[0004] The photodetector device is responsible for converting the ultraviolet light signal into an electrical signal and is the front-end device for ultraviolet detection. However, in the monitoring application of ultraviolet health protection, the skin damage related to the wavelength of ultraviolet rays prompts the photodetector to consider the wavelength-related responsivity performance.

[0005] Specifically, relevant research shows that when ultraviolet rays damage the skin and cause injuries such as erythema, the damage intensity of ultraviolet rays is often closely related to the wavelength of ultraviolet rays. Therefore, the International Organization for Standardization (ISO) and the Commission Internationale de l' CIE) have proposed the relationship between the relative coefficient of ultraviolet damage and the wavelength of ultraviolet rays as shown in Figure 2 the figure. This figure indicates that ultraviolet rays with shorter wavelengths have a stronger erythema damage effect on the skin. Taking a certain ultraviolet photodiode product on the market as an example, its responsivity related to the wavelength is as shown in Figure 3 the figure, which is different from the relationship between the responsivity of the reference diode and the wavelength. Therefore, it is of application value to use a detection device with a responsivity that more conforms to the above law in the application of ultraviolet skin damage detection.

[0006] In addition, the preparation and patterning of semiconductors have always been the key processes in the fabrication of semiconductor devices. After decades of development, semiconductor micro-nano processing technologies represented by silicon-based semiconductors are gradually approaching the nano-scale limit, which poses extremely high requirements for the patterning processing technology of semiconductor materials. However, currently, the common etching methods in semiconductor processing are used to achieve the patterning of materials. This subtractive method using liquid-phase etchants directly contacts the semiconductor surface, which may introduce reaction impurities and affect the electrical properties of the semiconductor. Therefore, in order to overcome the shackles of traditional semiconductor processing technologies, it is of great significance to invent an in-situ additive semiconductor patterning synthesis method.

[0007] Bi2O2Se is a two-dimensional, air-stable, high-mobility ternary semiconductor that exhibits extremely high carrier mobility, a moderate bandgap, excellent mechanical stability, and has a wide absorption spectrum (380 - 1600 nm) in the visible to near-infrared region, enabling rapid detection of infrared light. Its unique device structure can also achieve detection in the terahertz band. In the field of electrical devices, it has also shown excellent performance in the field of high-performance transistors due to its natural oxide layer with a high dielectric constant.

[0008] However, synthetic methods mainly based on chemical vapor deposition rarely achieve the large-area synthesis of large-area Bi2O2Se two-dimensional few-layer or quasi-two-dimensional thin films. Among them, the synthesis method of epitaxial growth on a lattice-matched compound substrate can obtain semiconductor materials with fewer defects, but the required lattice-matched epitaxial substrate brings problems of high cost and substrate limitation. In addition, although the spin-coating-selenization method on a mica substrate can obtain quasi-two-dimensional Bi2O2Se semiconductor thin films, subsequent patterning still relies on the liquid-phase etching method, and it is impossible to avoid damage to sensitive materials.

[0009] In the field of ultraviolet detection technology, for the application of monitoring the damage of ultraviolet rays to the skin, it is still challenging to achieve a miniaturized and portable detection device without a filter or special process. In addition, ultraviolet monitoring devices that conform to the spectral characteristics of ultraviolet damage are still not popular, which is a problem that needs to be overcome to achieve more accurate ultraviolet damage detection.

[0010] In the synthesis of semiconductor materials, the assembly method after the synthesis of two-dimensional semiconductors has high costs and complex processes, is selective for materials and substrates, and it is difficult to achieve large-area high-resolution patterning; during the in-situ growth process, high growth temperatures are involved; the top-down "growth and etching" route increases the complexity of the process; the thickness and morphology of the synthesized two-dimensional semiconductors are not easy to control. At the same time, the surface contamination introduced during the etching process will affect the quality of the nanomaterials. Therefore, it is necessary to find a suitable synthesis strategy to address the challenges faced in the patterned preparation of current nano-semiconductor materials. Summary of the Invention

[0011] To solve the above problems, the present invention provides a semiconductor optoelectronic device suitable for ultraviolet index monitoring and its application method, which is used to detect the ultraviolet index in the composite solar spectrum based on unique ultraviolet response characteristics.

[0012] A semiconductor optoelectronic device suitable for ultraviolet index monitoring includes a photosensitive device, a voltage source, and an ammeter connected in the same current loop;

[0013] Among them, the photosensitive device is composed of a quartz substrate, a Bi2O2Se thin film, and two Cr / Au metal electrodes covering the Bi2O2Se; among them, the Bi2O2Se thin film is coated on the quartz substrate in the form of a square array, one of the Cr / Au metal electrodes is connected to the positive pole of the voltage source, and the other Cr / Au metal electrode is connected to the negative pole of the voltage source through the ammeter; the voltage source is used to provide power for the photosensitive device, and the resistance value of the photosensitive device changes with the change of the ultraviolet index, and the reading of the ammeter changes with the change of the resistance value of the photosensitive device.

[0014] Further, when the ultraviolet index is a fixed value, the resistance value of the photosensitive device becomes smaller as the ultraviolet irradiation time increases.

[0015] Further, the Cr / Au metal electrode is composed of a rectangular body and a strip-shaped branch grown on one of the sides of the rectangular body; at the same time, the strip-shaped branches of the two Cr / Au metal electrodes are embedded in the pores of the strip-shaped branches of each other to form an interdigitated structure.

[0016] Further, the interval between two adjacent strip-shaped branches belonging to the same Cr / Au metal electrode is 10 μm.

[0017] Further, the preparation method of the Bi2O2Se thin film in the photosensitive device is as follows:

[0018] S100, deposit and synthesize a patterned metallic bismuth thin film on a quartz substrate by a lift-off process combined with photolithography;

[0019] S200, place the sample with the patterned metallic bismuth on its surface in a muffle furnace for thermal annealing to oxidize the bismuth on its surface into bismuth oxide;

[0020] S300, subject the quartz substrate with the patterned bismuth oxide thin film to selenization in a tube furnace to obtain a patterned Bi2O2Se thin film.

[0021] Further, an application method of a semiconductor optoelectronic device suitable for ultraviolet index monitoring includes the following steps:

[0022] Step 1: Set the calibrated UVI indices to 0, 2, 4, 6, 8, and 10 respectively;

[0023] Step 2: Irradiate the photosensitive device with ultraviolet light at each calibrated index respectively, and obtain the ammeter readings at the sampling moments during the entire irradiation period;

[0024] Step 3: Fit the ammeter reading sequences corresponding to each calibrated index respectively to obtain the standard current-time response curves corresponding to each calibrated index;

[0025] Step 4: Place the semiconductor optoelectronic device in the ultraviolet light environment to be measured for irradiation, and obtain the ammeter readings at set time intervals during the irradiation process;

[0026] Step 5: Fit the ammeter reading sequence corresponding to the ultraviolet light environment to be measured to obtain the measured current-time response curve corresponding to the ultraviolet light environment to be measured;

[0027] Step 6: Compare the measured current-time response curve with the standard current-time response curves corresponding to each calibrated index, obtain the two standard current-time response curves closest to the measured current-time response curve, and use the calibrated indices corresponding to the two curves as the interval where the ultraviolet index of the ultraviolet light environment to be measured is located.

[0028] Further, at the same bias voltage, the stronger the ultraviolet index, the greater the slope of the current-time response curve, and the higher the sensitivity of the semiconductor optoelectronic device.

[0029] Beneficial effects:

[0030] 1. The present invention provides a semiconductor optoelectronic device suitable for ultraviolet index monitoring, which can extract ultraviolet band signals under the solar spectrum, ignore signals in other bands, and its response characteristics enhance with time. Compared with existing silicon-based detectors, the present invention can detect the ultraviolet intensity under the composite spectrum without the need to rely on the anti-reflection film process or the combination of filters to detect the ultraviolet light signal in the ultraviolet band; in short, while the semiconductor optoelectronic detection device proposed by the present invention can detect visible light, it can detect the ultraviolet index under the solar spectrum without being affected by non-ultraviolet bands. The specificity related to the action time enables the interference of visible light band signals to be ignored during long-term detection, and there is no need to rely on filters to extract ultraviolet band signals. In addition, the relationship between the detected signal intensity and the ultraviolet wavelength conforms to the correlation between the damage coefficient and the ultraviolet wavelength proposed by the International Organization for Standardization, indicating that the device has certain application value in ultraviolet damage detection under sunlight.

[0031] 2. The present invention provides a semiconductor optoelectronic device suitable for ultraviolet index monitoring. The synthesis path of the Bi2O2Se thin film is in-situ and bottom-up: Bi → Bi2O3 → Bi2O2Se. Such an in-situ chemical synthesis path not only has controllable morphology, high pattern accuracy, but also has the advantage of large-area synthesis. It can be directly grown on any substrate without being restricted by lattice matching, overcoming the selectivity of the substrate, and enabling the synthesis of high-resolution and large-area Bi2O2Se semiconductor materials.

[0032] 3. The present invention provides an application method for a semiconductor optoelectronic device suitable for ultraviolet index monitoring. Based on the characteristic that the resistance value of the photosensitive device changes with the change of the ultraviolet index, a new ultraviolet index monitoring method is proposed, which is beneficial to more accurately predict the damage of ultraviolet rays to the skin and demonstrates the applicability for the monitoring of ultraviolet-damaged skin. Description of the Drawings

[0033] Figure 1 It is a schematic diagram of the characteristics of UVB and UVA ultraviolet damage;

[0034] Figure 2 It is the standard erythema damage coefficient (from ISO-CIE, 1999);

[0035] Figure 3 It is the light response curve of a certain commercial ultraviolet diode;

[0036] Figure 4 It is a schematic structural diagram of the semiconductor optoelectronic device suitable for ultraviolet index monitoring provided by the present invention;

[0037] Figure 5 It is the interdigitated channel pattern provided by the present invention;

[0038] Figure 6 The 1V bias voltage provided by the present invention, 0.5 mW / cm 2 Current-time response curves under different wavelength lasers at a power density;

[0039] Figure 7 Under the 1V bias voltage provided by the present invention, at the same optical power density, the relationship between the increasing slope of the detected electrical signal and the wavelength;

[0040] Figure 8 Under the 1V bias voltage provided by the present invention, the relationship curve between the change slope of the current signal and the power under different wavelength optical signals;

[0041] Figure 9 Is the AM 1.5G standard solar spectrum;

[0042] Figure 10 Under the 1V bias voltage provided by the present invention, the relative responsivity normalized to the wavelength in different wavelength ranges under the standard solar spectrum;

[0043] Figure 11 Under the 1V bias voltage provided by the present invention, current-time response curves under different ultraviolet indices UVI and dark conditions under the AM1.5G standard solar spectrum distribution;

[0044] Figure 12 Synthesis flow chart of the semiconductor optoelectronic device provided by the present invention;

[0045] Figure 13 3D schematic diagram of the high-resolution patterned Bi2O2Se semiconductor thin film provided by the present invention;

[0046] Figure 14 AFM thickness analysis of the Bi2O2Se semiconductor thin film provided by the present invention;

[0047] Figure 15 Large-area patterned sample provided by the present invention;

[0048] Figure 16 SEM image of the micron-resolution level array semiconductor thin film with electrodes added at both ends provided by the present invention;

[0049] 1-AR-P-5350 photoresist; 2-quartz glass; 3-thin film of metallic bismuth; 4-thin film of bismuth oxide; 5-Bi2O2Se thin film. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application.

[0051] As Figure 4As shown, a semiconductor optoelectronic device suitable for ultraviolet index monitoring includes a photosensitive device, a voltage source, and an ammeter connected in the same current loop;

[0052] Among them, the photosensitive device is composed of a quartz substrate, a Bi2O2Se thin film, and two Cr / Au metal electrodes covering the Bi2O2Se; among them, the Bi2O2Se thin film is coated on the quartz substrate in the form of a square array, one of the Cr / Au metal electrodes is connected to the positive pole of the voltage source, and the other Cr / Au metal electrode is connected to the negative pole of the voltage source through the ammeter; the voltage source is used to provide power for the photosensitive device, and the resistance value of the photosensitive device changes with the change of the ultraviolet index, and the reading of the ammeter changes with the change of the resistance value of the photosensitive device; when the ultraviolet index is a fixed value, the resistance value of the photosensitive device becomes smaller with the increase of the ultraviolet irradiation time.

[0053] Furthermore, the Cr / Au metal electrode is composed of a rectangular body and a strip-shaped branch grown on one of the sides of the rectangular body; at the same time, the strip-shaped branches of the two Cr / Au metal electrodes are embedded in the pores of the strip-shaped branches of each other to form an interdigitated structure; the interval between two adjacent strip-shaped branches belonging to the same Cr / Au metal electrode is 10 μm, and the thickness of the metal Cr / Au is 5 / 50 nm, as Figure 5 shown.

[0054] It should be noted that Bi2O2Se is an environmentally friendly ternary semiconductor material, which has good absorption in the ultraviolet-visible light band. When the photosensitive area of the device receives a light signal, it generates photogenerated carrier pairs, and its high carrier mobility enables the photogenerated carriers to migrate quickly. Therefore, it can achieve fast and effective photodetection function. However, the photoconductive detection device implemented by the present invention can also achieve unique detection of the light intensity in the ultraviolet band.

[0055] Under the bias voltage of 1V, under different wavelength light with the same power density, the response current-time curve of the device is as Figure 6 shown. The device makes a fast and effective photoconductive response to the visible light signal of unified power. However, for the light in the ultraviolet band, the device exhibits unique detection characteristics: that is, with the reception of the ultraviolet light signal, the converted electrical signal gradually increases with time. It should be emphasized that this unique detection characteristic is not only related to the intensity of ultraviolet light, but also related to the wavelength of ultraviolet light. Figure 7 For a certain power density (0.5 mW / cm 2 ), the relationship between the growth rate of the electrical signal and the wavelength under different wavelength light conditions, Figure 8 is the relationship between the increase rate of the electrical signal and the power under different wavelengths. The above two test results show that in the ultraviolet band detection of this device: the shorter the wavelength and the stronger the power, the stronger the ultraviolet detection signal.Figure 7 It is shown that the detection intensity of the device in the ultraviolet band conforms to the relationship between the erythema effectiveness coefficient and the wavelength mentioned above: in the UVA and UVB bands, the shorter the wavelength of ultraviolet light, the stronger its damage, indicating that the device is suitable for the detection application of ultraviolet radiation damage.

[0056] Based on the above-mentioned ultraviolet signal detection characteristics, under the simulated solar spectrum (AM 1.5G) with a standard intensity of 1000W / cm 2 ), its spectral irradiance is as Figure 9 shown. This solar spectrum conforms to the solar spectrum reaching the earth's surface in reality. Due to the strong reflection of ultraviolet light by the atmosphere, only relatively small amounts of UVA and UVB bands reach the earth's surface. In order to verify the ability of the device to extract the ultraviolet index from solar composite light in the simulated outdoor light environment, band-pass filters of different bands were used in the above-mentioned simulated sunlight environment, and the response time curves normalized to the light power density of different bands were obtained, as Figure 10 shown. This figure shows that only the light in the ultraviolet band in the solar spectrum has the ability to continuously enhance the detection signal.

[0057] The ultraviolet index classifies the ultraviolet intensity from weak to strong. When its value is 0-2, it has basically no effect on the human body; when the value is 3-4, the damage is low; when the value is 5-6, it will cause moderate damage to the human body. According to the detection ability of the above device, the device was tested for the ultraviolet index under the simulated sunlight with the AM1.5G standard spectral distribution corresponding to different ultraviolet index intensities using a commercial ultraviolet index detector, as Figure 11 shown.

[0058] It can be seen that the optoelectronic device provided by the present invention has the characteristic of an electrical signal obtained by converting ultraviolet light that increases with time, which is rarely found in the current commercial or research fields.

[0059] Next, a method based on a large-area micron-scale resolution patterning synthesis path is used to prepare the Bi2O2Se thin film in the photosensitive device.

[0060] Figure 12 Schematically shows a micro-nano patterning synthesis method of a semiconductor provided by an embodiment of the present invention. This method includes steps S100-S400, as Figure 12 shown.

[0061] S100, synthesize a patterned bismuth metal thin film on a quartz substrate by combining the lift-off process of photolithography. Use AR-P-5350 photoresist for the lift-off process of photolithography.

[0062] The above process sequentially includes substrate cleaning, spin coating, pre-baking, exposure, development, evaporation coating, and resist stripping. Among them, substrate cleaning: clean the quartz glass substrate (the substrate can also be selected as silicon dioxide wafer, silicon wafer, glass, mica, etc.), and ultrasonically clean the quartz substrate with acetone, water, and ethanol in sequence. Spin coating: Use photoresist AR-P-5350 to spin coat on the cleaned quartz substrate 2 at a rotation speed of 2000 r / min to obtain a sample as shown in step (Ⅰ) of Figure 12 . Pre-baking: The quartz substrate coated with photoresist is placed on a hot plate. Exposure: Use an ultraviolet light source for mask exposure. Development: Immerse the sample in a mixed solution of AR300-26: deionized water for about 10 s for development to obtain a sample as shown in step (Ⅱ) of Figure 12 .

[0063] S200, evaporate metal bismuth on the post-lithography sample.

[0064] Evaporation coating process: In a vacuum environment (with the air pressure between 0.000005 Pa and 0.0001 Pa), heat and evaporate the bismuth powder in the tantalum boat, and evaporate a metal bismuth thin film with a thickness of 10 nm - 20 nm onto the developed quartz substrate to obtain a sample as shown in step (Ⅲ) of Figure 12 .

[0065] Then immerse the sample in acetone for several minutes to remove the photoresist, and obtain a patterned metal bismuth precursor thin film 3 on the quartz substrate to obtain a sample as shown in step (Ⅳ) of Figure 12 .

[0066] S300, place the sample with the patterned metal bismuth on a muffle furnace for thermal annealing to oxidize the bismuth on its surface to form bismuth oxide.

[0067] Use a muffle furnace to perform oxidation annealing on the sample in an atmospheric environment at 300 °C to obtain a patterned bismuth oxide thin film 6, as shown in step (Ⅴ) of Figure 12 .

[0068] S400, perform selenization on the quartz substrate with the patterned bismuth oxide thin film in a tube furnace to obtain a patterned Bi2O2Se thin film, and its 3D schematic diagram is as shown in Figure 13 .

[0069] Place it in a double-heating-zone quartz tube furnace, place the selenium grains in the upstream heating zone, place the sample substrate in the downstream heating zone, in an argon gas environment with a flow rate of several hundred, and heat the upstream and downstream heating zones to 350 °C and 350 °C respectively to obtain a patterned Bi2O2Se thin film 5, as shown in step (Ⅵ) of Figure 12 , and in addition, the thickness of the patterned semiconductor thin film was analyzed by an atomic force microscope (AFM) characterization method to be about 25 nm, as shown in Figure 14 .

[0070] Through the above method, the patterning of semiconductor thin films can be achieved on a large-area substrate, such as the "zebra" patterned thin film shown in Figure 15 . In addition, this process can achieve high-density patterns with a micron-level resolution accuracy. This embodiment demonstrates an array of patterned semiconductor thin films, with each thin film having a size of 6μm * 2μm. Considering subsequent testing as photosensitive elements, the above-mentioned lift-off method assisted by lithography was used to fabricate metal electrodes with a size of 2μm * 2μm added at both ends of the thin film, and its surface SEM is shown in Figure 16 .

[0071] It should be noted that the current patterning methods for Bi2O2Se mainly rely on wet oxidation-reduction etching combined with lithography processes: using a mixed solution of hydrogen peroxide, sulfuric acid, and water with a specific ratio to etch Bi2O2Se with different thicknesses at different doses. Such complex methods that require precise control of the etching dose not only reduce the material, generate other residues, but also introduce impurities on the material surface; in addition, in the current synthesis and fabrication schemes for two-dimensional Bi2O2Se semiconductors, many methods involve the transfer of substrates, and in addition, some epitaxial methods require lattice matching of the substrates; however, the proposed patterning synthesis method of semiconductor thin films in the present invention avoids the influence of subtractive processes and etching residues, and realizes the synthesis of high-resolution patterned semiconductors without introducing impurities on the surface by virtue of the bottom-up synthesis strategy of Bi→Bi2O3→Bi2O2Se and the mature and effective lithography process, and can be directly applied to the fabrication and application of the next semiconductor devices.

[0072] Furthermore, in a certain specific range of the ultraviolet band of the optoelectronic device fabricated by the present invention, the smaller the wavelength of the ultraviolet light, the faster the change rate of the response electrical signal. This relationship between the electrical signal and the wavelength is of great significance in the application of ultraviolet light damaging the skin, and is rare in the current third-generation semiconductors used for ultraviolet monitoring; based on this, the present invention also provides an application method for a semiconductor optoelectronic device suitable for ultraviolet index monitoring, including the following steps:

[0073] Step 1: Set the calibrated UVI indices to 0, 2, 4, 6, 8, and 10 respectively;

[0074] It should be noted that the UVI indices set by the present invention are included under the light of 300nm–2500nm in the AM1.5G standard sunlight composite spectrum;

[0075] Step 2: Irradiate the photosensitive device with ultraviolet light at each calibrated index respectively, and obtain the ammeter readings at the sampling moments during the entire irradiation period;

[0076] Step 3: Fit the ammeter reading sequences corresponding to each calibrated index respectively to obtain the standard current-time response curves corresponding to each calibrated index;

[0077] Step 4: Place the semiconductor optoelectronic device in the ultraviolet light environment to be measured for irradiation, and obtain the ammeter readings at set time intervals during the irradiation process;

[0078] Step 5: Fit the ammeter reading sequence corresponding to the ultraviolet light environment to be measured to obtain the measured current-time response curve corresponding to the ultraviolet light environment to be measured;

[0079] Step 6: Compare the measured current-time response curve with the standard current-time response curves corresponding to each calibration index, obtain the two standard current-time response curves closest to the measured current-time response curve, and use the corresponding calibration indices of the two as the interval where the ultraviolet index of the ultraviolet light environment to be measured is located.

[0080] It can be seen that the optoelectronic device proposed by the present invention can extract the electrical signal of the device for ultraviolet light signal in the ultraviolet band, and this signal can be enhanced for up to dozens of minutes so that the influence of visible light signals can be ignored. This characteristic enables it to monitor the ultraviolet intensity in sunlight in outdoor scenarios.

[0081] It should be noted that the relationship between the electrical signal response intensity of the optoelectronic device fabricated by the present invention in the ultraviolet band and the intensity and wavelength of ultraviolet light conforms to the characteristics of ultraviolet light damaging the skin proposed by the International Organization for Standardization: the stronger the ultraviolet light intensity and the shorter the wavelength, the stronger the effect of damaging the skin. Such characteristics are rarely concerned and difficult to achieve by current detectors in this application field. Therefore, in terms of wavelength, using this type of optoelectronic device can detect ultraviolet damage more accurately and is more suitable for monitoring the degree of damage of ultraviolet light to the skin.

[0082] Certainly, the present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can of course make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present invention.

Claims

1. A semiconductor optoelectronic device suitable for ultraviolet index monitoring, characterized in that, It includes a photosensitive device, a voltage source, and an ammeter connected in the same current loop; Among them, the photosensitive device is composed of a quartz substrate, a Bi2O2Se thin film, and two Cr / Au metal electrodes covering the Bi2O2Se. Among them, the Bi2O2Se thin film is coated on the quartz substrate in the form of a square array. One of the Cr / Au metal electrodes is connected to the positive pole of the voltage source, and the other Cr / Au metal electrode is connected to the negative pole of the voltage source through the ammeter. The voltage source is used to provide power for the photosensitive device, and the resistance value of the photosensitive device changes with the change of the ultraviolet index, and the reading of the ammeter changes with the change of the resistance value of the photosensitive device.

2. The semiconductor optoelectronic device applicable to ultraviolet index monitoring according to claim 1, wherein When the ultraviolet index is a fixed value, the resistance value of the photosensitive device becomes smaller with the increase of the ultraviolet irradiation time.

3. The semiconductor optoelectronic device applicable to ultraviolet index monitoring according to claim 1, wherein, The Cr / Au metal electrode consists of a rectangular body and a strip-shaped branch grown on one side of the rectangular body. At the same time, the strip-shaped branches of the two Cr / Au metal electrodes are embedded in the pores of the strip-shaped branches of each other to form an interdigitated structure.

4. A semiconductor optoelectronic device applicable to ultraviolet index monitoring according to claim 3, characterized in that, The interval between two adjacent strip-shaped branches belonging to the same Cr / Au metal electrode is 10 μm.

5. A semiconductor optoelectronic device applicable to ultraviolet index monitoring as described in claim 1, characterized in that, The preparation method of the Bi2O2Se thin film in the photosensitive device is as follows: S100, evaporate and deposit a patterned metallic bismuth thin film on the quartz substrate by using a lift-off process combined with photolithography; S200, place the sample with the patterned metallic bismuth on the surface in a muffle furnace for thermal annealing so that the bismuth on its surface is oxidized to become bismuth oxide; S300, selenize the quartz substrate with the patterned bismuth oxide thin film in a tube furnace to obtain a patterned Bi2O2Se thin film.

6. An application method of the semiconductor optoelectronic device applicable to ultraviolet index monitoring according to claim 1, characterized in that, It includes the following steps: Step 1: Set the calibrated UVI indexes to 0, 2, 4, 6, 8, and 10 respectively; Step 2: Irradiate the photosensitive device with ultraviolet light at each calibrated index respectively, and obtain the ammeter readings at the sampling moments during the entire irradiation time period; Step 3: Fit the ammeter reading sequences corresponding to each calibrated index respectively to obtain the standard current-time response curves corresponding to each calibrated index; Step 4: Place the semiconductor optoelectronic device in the ultraviolet light environment to be measured for irradiation, and obtain the ammeter readings at the set time intervals during the irradiation process; Step 5: Fit the ammeter reading sequence corresponding to the ultraviolet light environment to be measured to obtain the measured current-time response curve corresponding to the ultraviolet light environment to be measured; Step 6: Compare the measured current-time response curve with the standard current-time response curves corresponding to each calibrated index, obtain the two standard current-time response curves closest to the measured current-time response curve, and use the calibrated indexes corresponding to the two as the interval where the ultraviolet index of the ultraviolet light environment to be measured is located.

7. The application method according to claim 6, wherein Under the same bias voltage, the stronger the ultraviolet index, the greater the slope of the current-time response curve, and the higher the sensitivity of the semiconductor optoelectronic device.

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