A UV power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector

Abstract

The present invention discloses an ultraviolet light power meter based on a n-ZnO:Ga / p-GaN heterojunction photodetector probe, including a heterojunction photodetector probe, a differential I / V conversion module, an ADC module, an MCU module, an OLED module, and a power module. Compared with the prior art, the present invention prepares an n-ZnO:Ga / p-GaN heterojunction ultraviolet photodetector probe and adopts a differential I / V conversion module to convert a current signal into a voltage signal and effectively filter out dark current; the MCU calculates and outputs the displayed light power density in real time, and an alarm is generated if the ultraviolet light power density threshold set manually is exceeded; and a ultraviolet light power meter based on low-dimensional photoelectric devices is provided, which has low requirements on test equipment and is more practical in daily life.

Description

Technical Field

[0001] The invention relates to the technical field of optical power testing equipment, and in particular to an ultraviolet light power meter based on an n-ZnO:Ga / p-GaN heterojunction photoelectric detector probe. Background Art

[0002] The ultraviolet power meter is an optical measuring instrument for measuring the power density of ultraviolet light. It has important applications in the fields of solar radiation, missile warning, flame detection, photophysical testing, etc. The ultraviolet photodetector is the core device for building the ultraviolet power meter. It can convert the ultraviolet radiation signal into an electrical signal based on the external photoelectric effect. At present, the ultraviolet photodetector has gone through several stages of development. Compared with the ultraviolet photodetector based on silicon materials, the wide bandgap ultraviolet detector has greater development potential in the field of high temperature and high frequency. ZnO micron wire is the preferred material for preparing ultraviolet photodetector due to its wide direct band gap, high electron mobility and small volume. The Chinese patent with publication number CN117476788 A discloses a self-driven ultraviolet photodetector based on Ga-doped ZnO micron wire and its preparation method. The prepared self-driven ultraviolet detector can certainly achieve high response and high sensitivity ultraviolet detection, but the device is strongly dependent on experimental equipment and cannot be truly applied in daily life. Therefore, it is necessary to develop a new type of measuring device. Summary of the invention

[0003] Purpose of the invention: To solve the above problems, the present invention provides an ultraviolet light power meter based on an n-ZnO:Ga / p-GaN heterojunction photodetector probe. By preparing an n-ZnO:Ga / p-GaN heterojunction ultraviolet photodetector probe and adopting a differential I / V conversion module, the current signal is converted into a voltage signal and the dark current is effectively filtered out; the light power density is calculated and output in real time by an MCU, and an alarm is generated if it exceeds a manually set ultraviolet light power density threshold; a ultraviolet light power meter based on low-dimensional optoelectronic devices is provided, which has low requirements on test equipment and is more practical in daily life.

[0004] Technical solution: To achieve the above-mentioned purpose, the ultraviolet light power meter based on the n-ZnO:Ga / p-GaN heterojunction photodetector probe described in the present invention includes a first n-ZnO:Ga / p-GaN heterojunction photodetector probe, a second n-ZnO:Ga / p-GaN heterojunction photodetector probe, a differential I / V conversion module, an ADC module connected to the differential I / V conversion module, an MCU module connected to the ADC module, an OLED module connected to the MCU module, and a power module; the differential I / V conversion module includes a first operational amplifier module connected to the first n-ZnO:Ga / p-GaN heterojunction photodetector probe, a second operational amplifier module connected to the second n-ZnO:Ga / p-GaN heterojunction photodetector probe, and a third operational amplifier module connected in series with the first operational amplifier module and the second operational amplifier module.

[0005] Furthermore, the structures of the first n-ZnO:Ga / p-GaN heterojunction photodetector probe and the second n-ZnO:Ga / p-GaN heterojunction photodetector probe are both n-ZnO:Ga / p-GaN heterojunction constructed by Ga-doped ZnO microwires and GaN thin films.

[0006] Furthermore, the first operational amplifier module includes an operational amplifier OPA1, a resistor R1 connected in parallel with the negative input terminal of the operational amplifier OPA1, and a capacitor C1 connected in parallel with the negative input terminal of the operational amplifier OPA1; the second operational amplifier module includes an operational amplifier OPA2, a resistor R2 connected in parallel with the negative input terminal of the operational amplifier OPA2, and a capacitor C2 connected in parallel with the negative input terminal of the operational amplifier OPA2; the positive input terminals of the operational amplifier OPA1 and the operational amplifier OPA2 are both connected to the ground wire.

[0007] Furthermore, the values ​​of the capacitor C1 and the capacitor C2 are consistent, and the value range of the capacitor C1 and the capacitor C2 is 10fF to 1pF.

[0008] Furthermore, the values ​​of the resistor R1 and the resistor R2 are consistent, and the value range of the resistor R1 and the resistor R2 is 1 kΩ to 1000 kΩ.

[0009] Furthermore, the third operational amplifier module includes an operational amplifier OPA3, a resistor R3 connected in series with the first operational amplifier module, a resistor R4 connected in series with the second operational amplifier module, a resistor R5 connected in parallel with the negative input terminal of the operational amplifier OPA3, and a resistor R6 connected to the positive input terminal of the operational amplifier OPA3, and the resistor R6 is connected to the ground wire.

[0010] Furthermore, the values ​​of the resistors R3, R4, R5 and R6 are consistent, and the value ranges of the resistors R3, R4, R5 and R6 are all between 1 kΩ and 1000 kΩ.

[0011] Furthermore, the optical power density calculation formula built into the MCU module is:

[0012] I=AP θ , that is, P = log θ I-log θ A, where I represents photocurrent, P represents light power density, A represents the response coefficient of photocurrent to illumination, and θ represents the response index of photocurrent to illumination. The size of A and θ is determined by the device itself.

[0013] Furthermore, the operational amplifier OPA1, operational amplifier OPA2 and operational amplifier OPA3 are all connected to a power supply module, and the power supply module is powered by a single power supply.

[0014] Furthermore, the n-ZnO:Ga / p-GaN heterojunction photoelectric detector probe adopts a split design.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant effects: by preparing an n-ZnO:Ga / p-GaN heterojunction ultraviolet photodetector probe and adopting a differential I / V conversion module, the current signal is converted into a voltage signal and the dark current is effectively filtered out, thereby realizing an independent, high-performance, and low-power working mode of the device, meeting the application requirements of future optoelectronic devices; the light power density is calculated and output in real time by the MCU, and an alarm is issued if it exceeds a manually set ultraviolet light power density threshold; the probe adopts a split design, and different micron-wire-based photodetector probes are replaced according to the actual power density detection requirements, thereby enhancing the compatibility of the power meter, thereby providing an ultraviolet light power meter based on low-dimensional optoelectronic devices that has low requirements on test equipment and is more practical in daily life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the workflow of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of the ultraviolet photoelectric detector described in the present invention.

[0018] Figure 3 The n-ZnO:Ga / p-GaN heterojunction structure of the present invention is in a dark environment and under light (365nm136mW / cm 2 )'s IV logarithmic characteristic curve.

[0019] Figure 4It is the It characteristic curve of the ultraviolet photodetector of the present invention when it is repeatedly switched on and off under light of different power densities with a wavelength of 365nm under 0V bias.

[0020] Figure 5 The photocurrent-optical power density curve of the ultraviolet photodetector described in the present invention under 0V bias and light with a wavelength of 365nm. DETAILED DESCRIPTION

[0021] The present invention discloses an ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe. Figures 1 to 5As shown, the ultraviolet light power meter based on the n-ZnO:Ga / p-GaN heterojunction photodetector probe provided by the present invention is further described in detail below: The ultraviolet light power meter based on the n-ZnO:Ga / p-GaN heterojunction photodetector probe includes a first n-ZnO:Ga / p-GaN heterojunction photodetector probe 1, a second n-ZnO:Ga / p-GaN heterojunction photodetector probe 2, a differential I / V conversion module, an ADC module connected to the differential I / V conversion module, an MCU module connected to the ADC module, an OLED module connected to the MCU module, and a power module. Among them, the differential I / V conversion module includes a first operational amplifier module connected to the first n-ZnO:Ga / p-GaN heterojunction photodetector probe 1, a second operational amplifier module connected to the second n-ZnO:Ga / p-GaN heterojunction photodetector probe 2, and a third operational amplifier module connected in series with the first operational amplifier module and the second operational amplifier module. The structures of the first n-ZnO:Ga / p-GaN heterojunction photodetector probe 1 and the second n-ZnO:Ga / p-GaN heterojunction photodetector probe 2 are both n-ZnO:Ga / p-GaN heterojunctions constructed by Ga-doped ZnO micrometer wires (ZnO:Ga MW) and GaN thin films. The first operational amplifier module includes an operational amplifier OPA1, a resistor R1 connected in parallel with the negative input terminal of the operational amplifier OPA1, and a capacitor C1 connected in parallel with the negative input terminal of the operational amplifier OPA1. The second operational amplifier module includes an operational amplifier OPA2, a resistor R2 connected in parallel with the negative input terminal of the operational amplifier OPA2, and a capacitor C2 connected in parallel with the negative input terminal of the operational amplifier OPA2; the positive input terminals of the operational amplifier OPA1 and the operational amplifier OPA2 are both connected to the ground wire. The values ​​of capacitor C1 and capacitor C2 are consistent, and the value range of capacitor C1 and capacitor C2 is 10fF~1pF; the values ​​of resistor R1 and resistor R2 are consistent, and the value range of resistor R1 and resistor R2 is 1kΩ~1000KΩ. The third operational amplifier module includes operational amplifier OPA3, resistor R3 connected in series with the first operational amplifier module, resistor R4 connected in series with the second operational amplifier module, resistor R5 connected in parallel with the negative input terminal of operational amplifier OPA3, and resistor R6 connected to the positive input terminal of operational amplifier OPA3, and resistor R6 is connected to the ground wire; the values ​​of resistor R3, resistor R4, resistor R5 and resistor R6 are consistent, and the value range of resistor R3, resistor R4, resistor R5 and resistor R6 is between 1kΩ~1000KΩ. Operational amplifier OPA1, operational amplifier OPA2 and operational amplifier OPA3 are all connected to the power supply module, and the power supply module is powered by a single power supply. The n-ZnO:Ga / p-GaN heterojunction photodetector probe adopts a split design. The optical power density calculation formula built into the MCU module is:

[0022] I=APθ , that is, P = log θ I-log θ A, where I represents photocurrent (A) and P represents light power density (mW / cm 2 ), A represents the response coefficient of photocurrent to illumination, θ represents the response index of photocurrent to illumination, and the size of A and θ is determined by the device itself.

[0023] The differential I / V conversion module is used to convert the current signal into a voltage signal, and two relatively independent symmetrical I / V conversion amplifier circuits are used for differential processing; the current signals generated by the two identical detector probes under ultraviolet light irradiation conditions and light shielding conditions are used as the input sources of operational amplifiers OPA1 and OPA2, and the output signals of the two are subtracted by the subtraction circuit composed of OPA3, which can be equivalent to an I / V conversion circuit with only the photocurrent signal as the input source, and the interference of dark current and some noise signals can be simply and efficiently filtered out. The ADC conversion module is used to convert the voltage analog signal obtained by the differential I / V conversion module into a digital signal. In order to reduce the error, the ADC collects the voltage signal of the input port 20 times and calculates the average value. The MCU chip is used to control the sampling of the detector and the action of the ADC module. The MCU chip is used to receive data collection, calculation and command output, specifically to receive the digital signal obtained by the ADC module, convert it into the numerical value corresponding to the original analog current signal, calculate the power value by the power density calculation formula, and output the power value to the OLED display module after the calculation. The OLED display module is used as an output interface for human-computer interaction. It is used to receive instructions and signals transmitted by the MCU, and display the corresponding values ​​to show the data output of the optical power meter. The power module uses a single power supply, including a single power supply and a voltage conversion module. The power supply uses a +12V rechargeable lithium battery. The function of the voltage conversion module is to convert the +12V voltage to ±5V to provide working current for the entire optical power meter.

[0024] like Figure 2 As shown, the thickness of the quartz substrate 7 is 0.1 cm and the size is 3 cm×2.2 cm; the diameter of the ZnO:Ga microwire 4 is 10 μm and the length is 0.5 cm; the thickness of the GaN film 6 is 300-350 nm, the thickness of the copper film electrode 3 is 50-100 nm, and the thickness of the In electrode 5 is 50-100 nm.

[0025] like Figure 3 As shown, in the comparative experiment under 365nm illumination and dark conditions, the photocurrent is greater than the dark current under negative bias, and the difference is nearly two orders of magnitude, which proves that the photocurrent of the device is sensitive to 365nm detection, and the enhancement of the photocurrent under negative bias of the device is greater than the enhancement of the photocurrent under positive voltage, and the construction of the heterojunction photodetector is completed.

[0026] like Figure 4 As shown in the figure, the photocurrent and dark current have obvious changes, and the dark current is about 25nA. UV light detection can be achieved under 0V bias, which shows that the UV photodetector can work in self-powered mode. The six different power densities corresponding to the figure are 136mW / cm 2 、79.08mW / cm 2 、16.5mW / cm 2 、3.91mW / cm 2 、1.006mW / cm 2 , 0.481mW / cm 2 The corresponding photocurrents are 4.23μA, 3.81μA, 2.01μA, 1.44μA, and 1.11μA. The photocurrent is calculated as the average current value corresponding to 10s of illumination.

[0027] like Figure 5 As shown, the inherent properties of the device determine that there is a relationship between its photocurrent and optical power density: I = AP θ Relationship, where I, P, A, and θ represent photocurrent, light power density, the coefficient that determines the response of photocurrent to illumination, and the index that determines the response of photocurrent to illumination, respectively. The collection of the midpoint of the curve in the figure is based on Figure 4 The method is to change the light power density and repeat the experiment. Theoretically, the corresponding relationship between photocurrent and light power density is I = AP θ Determine that I and P satisfy the linear relationship after taking the logarithm, such as Figure 4 , the slope is 0.25, the intercept is -5.68, that is, A = e -5.68 ,θ=0.25,I=e -5.68 ·P 0.25 . Among them, A and θ values ​​are inherent parameters of the device, and different low-dimensional photoelectric detection devices correspond to different A and θ. The present invention is an optical power meter based on a low-dimensional photoelectric detector probe, wherein the photoelectric detector probe and the power meter host adopt a split design, and each module of the detector probe and the power meter host is relatively independent. The photoelectric detector probe can be replaced with different probes as needed, such as different detection bands and better accuracy requirements, thereby enhancing the compatibility of the power meter and being compatible with similar low-dimensional photoelectric detectors of different performances.

Claims

1. An ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe, characterized in that: The invention comprises a first n-ZnO:Ga / p-GaN heterojunction photodetector probe (1), a second n-ZnO:Ga / p-GaN heterojunction photodetector probe (2), a differential I / V conversion module, an ADC module connected to the differential I / V conversion module, an MCU module connected to the ADC module, an OLED module connected to the MCU module, and a power module; the differential I / V conversion module comprises a first operational amplifier module connected to the first n-ZnO:Ga / p-GaN heterojunction photodetector probe (1), a second operational amplifier module connected to the second n-ZnO:Ga / p-GaN heterojunction photodetector probe (2), and a third operational amplifier module connected in series with the first operational amplifier module and the second operational amplifier module.

2. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 1, characterized in that: The structures of the first n-ZnO:Ga / p-GaN heterojunction photodetector probe (1) and the second n-ZnO:Ga / p-GaN heterojunction photodetector probe (2) are both n-ZnO:Ga / p-GaN heterojunctions constructed by Ga-doped ZnO micrometer wires and GaN thin films.

3. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 1, characterized in that: The first operational amplifier module includes an operational amplifier OPA1, a resistor R1 connected in parallel with the negative input terminal of the operational amplifier OPA1, and a capacitor C1 connected in parallel with the negative input terminal of the operational amplifier OPA1; the second operational amplifier module includes an operational amplifier OPA2, a resistor R2 connected in parallel with the negative input terminal of the operational amplifier OPA2, and a capacitor C2 connected in parallel with the negative input terminal of the operational amplifier OPA2; the positive input terminals of the operational amplifier OPA1 and the operational amplifier OPA2 are both connected to the ground wire.

4. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 3, characterized in that: The values ​​of the capacitor C1 and the capacitor C2 are consistent, and the value range of the capacitor C1 and the capacitor C2 is 10fF to 1pF.

5. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 3, characterized in that: The values ​​of the resistor R1 and the resistor R2 are consistent, and the value range of the resistor R1 and the resistor R2 is 1kΩ~1000KΩ.

6. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 1, characterized in that: The third operational amplifier module includes an operational amplifier OPA3, a resistor R3 connected in series with the first operational amplifier module, a resistor R4 connected in series with the second operational amplifier module, a resistor R5 connected in parallel with the negative input terminal of the operational amplifier OPA3, and a resistor R6 connected to the positive input terminal of the operational amplifier OPA3, and the resistor R6 is connected to the ground wire.

7. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 6, characterized in that: The values ​​of the resistors R3, R4, R5 and R6 are consistent, and the value ranges of the resistors R3, R4, R5 and R6 are all between 1 kΩ and 1000 kΩ.

8. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 1, characterized in that: The optical power density calculation formula built into the MCU module is: I=AP θ , that is, P = log θ I-log θ A, where I represents photocurrent, P represents light power density, A represents the response coefficient of photocurrent to illumination, and θ represents the response index of photocurrent to illumination. The size of A and θ is determined by the device itself.

9. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 1, characterized in that: The operational amplifier OPA1, operational amplifier OPA2 and operational amplifier OPA3 are all connected to a power module, and the power module is powered by a single power supply.

10. The ultraviolet light power meter based on n-ZnO:Ga / p-GaN heterojunction photodetector probe according to claim 1, characterized in that: The n-ZnO:Ga / p-GaN heterojunction photoelectric detector probe adopts a split design.

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