Method and device for characterizing interface defects of optoelectronic devices

Abstract

The present invention relates to a method and device for characterizing interface defects of optoelectronic devices, which solves the technical problem that defects at the interface of optoelectronic devices in the prior art cannot be detected nondestructively. The method of the present invention includes: establishing an equivalent circuit model of the optoelectronic device to be measured; under a set DC bias voltage, according to the set temperature range and temperature step, at each temperature, varying the angular frequency of the AC voltage across the optoelectronic device to be measured, and using the equivalent circuit model to obtain a test curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtaining characteristic frequencies at different temperatures; linearly fitting the characteristic frequencies at different temperatures to obtain a straight-line slope; according to the straight-line slope, obtaining the activation energy and capture interface of the optoelectronic device, and characterizing the interface defects of the optoelectronic device according to the activation energy and capture interface, so as to realize nondestructive detection of the optoelectronic device.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic devices, and particularly to a method and device for detecting defects at the interface in an optoelectronic device. Background Art

[0002] In recent years, the field of optoelectronic devices such as solar cells or photodetectors has been continuously developing. The characteristics of the development are: increasing production, improving conversion efficiency, reducing costs, continuously expanding the application fields, and the requirements for detectors are to improve the detection accuracy and thus enhance the energy resolution.

[0003] For solar cells or photodetectors, the magnitude of leakage current has an extremely important impact. The commonly used method to reduce leakage current is to passivate with an ultrathin tunneling dielectric layer, which does not affect the electrical properties of the device itself during passivation. Therefore, the passivation effect is the core goal pursued in the industry. How to perform tests without separating the device into individual structures and ensuring the integrity of the device, so as to avoid introducing new defects and impurities, is the focus of current research.

[0004] In the prior art, there is a lack of a method and device for detecting defects at the interface in an optoelectronic device that can ensure the integrity of the device without damage. Summary of the Invention

[0005] The present invention aims to provide a method and device for detecting defects at the interface in an optoelectronic device, so as to solve the problem that defects at the interface of optoelectronic devices in the prior art cannot be detected without damage.

[0006] To achieve the above object, the following technical solutions are provided in the embodiments of the present invention:

[0007] In the first aspect of the embodiments of the present invention, a method for detecting defects at the interface in an optoelectronic device is provided, including:

[0008] Establish an equivalent circuit model of the optoelectronic device to be tested;

[0009] Under a set DC bias voltage, according to the set temperature range and temperature step, at each temperature, vary the angular frequency of the AC voltage across the optoelectronic device to be tested, and use the equivalent circuit model to obtain a test curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtain characteristic frequencies at different temperatures;

[0010] According to the characteristic frequencies at different temperatures, linearly fit to obtain a straight-line slope;

[0011] According to the straight-line slope, obtain the activation energy and capture interface of the optoelectronic device, and characterize the interface defects of the optoelectronic device according to the activation energy and capture interface.

[0012] Further, an equivalent circuit model of the optoelectronic device to be measured is established, and the equivalent circuit model is expressed as:

[0013]

[0014] where C is the total capacitance, e p is the emission rate of holes, β is the first constant, ω is the angular frequency of the alternating voltage, and C0 is the total capacitance corresponding to when the angular frequency of the alternating voltage approaches infinity.

[0015] Further, under the condition of no light, a DC bias voltage is set across the optoelectronic device to be measured, and the temperature range and temperature step size are set, and the temperature is Fahrenheit;

[0016] The obtained characteristic frequencies at different temperatures include:

[0017] At each temperature, under the DC bias voltage set across the optoelectronic device to be measured, by varying the angular frequency ω of the alternating voltage across the optoelectronic device to be measured, using the equivalent circuit model, a C-ω / 2π curve of the total capacitance of the optoelectronic device changing with the angular frequency is obtained, and the total capacitance C0 corresponding to when the angular frequency of the alternating voltage approaches infinity is obtained;

[0018] According to the C-ω / 2π curve and the total capacitance C0 corresponding to when the angular frequency of the alternating voltage approaches infinity, an ωdC / dω-ω / 2π curve is plotted, and the angular frequency at the extreme point of the ωdC / dω-ω / 2π curve is the characteristic frequency ω at the temperature. p .

[0019] Further, according to each temperature T and the corresponding characteristic frequency, a straight line of ln(ω p / T 2 )-1 / T is fitted, and the slope S of the straight line is calculated;

[0020] According to the slope of the straight line, the activation energy and the capture interface of the optoelectronic device are obtained, including:

[0021] Based on the theoretical relationship between ω p and temperature T, and the slope S of the straight line, the activation energy E a is obtained, and the intercept on the ln(ω p / T 2 )-1000 / T straight line corresponding to the ln(ω p / T 2 ) axis is the capture interface σ n .

[0022] Further, the theoretical relationship between ω p and temperature T is obtained by the following formula:

[0023]

[0024] Among them, e p is the emission rate of holes, σ is the defect capture area, and v th is the carrier movement speed and is proportional to T 12 N v is the valence band density of states and is proportional to T 32 E a is the activation energy, k is the Boltzmann constant, and α is the second constant.

[0025] Furthermore, setting the DC bias voltage includes:

[0026] At room temperature, set the initial DC bias voltage and the initial DC bias voltage step size;

[0027] At each initial DC bias voltage, measure the total capacitance C and the initial DC bias voltage, obtain the C-V curve, and determine the range of the DC bias voltage according to the C-V curve;

[0028] Within the range of the DC bias voltage, set the DC bias voltage step size;

[0029] At each DC bias voltage, by varying the angular frequency ω of the AC voltage across the optoelectronic device to be measured, obtain the C-ω / 2π curve at different DC bias voltages, and set the DC bias voltage according to the C-ω / 2π curves at different DC bias voltages.

[0030] Furthermore, setting the temperature range and the temperature step size includes:

[0031] At the set DC bias voltage, set the initial temperature range and the initial temperature step size;

[0032] By varying the angular frequency ω of the AC voltage across the optoelectronic device to be measured, obtain the C-ω / 2π curve of the total capacitance of the optoelectronic device varying with the angular frequency at each initial temperature;

[0033] Determine the temperature range according to the C-ω / 2π curves of the total capacitance of the optoelectronic device varying with the angular frequency at each initial temperature, and set the temperature step size from the temperature range.

[0034] In another aspect of the embodiments of the present invention, a defect detection device at the interface in an optoelectronic device is provided, including:

[0035] A model establishment module for establishing an equivalent circuit model of the optoelectronic device to be measured;

[0036] A characteristic frequency acquisition module, configured to, under a set DC bias voltage, vary the angular frequency of the AC voltage across the optoelectronic device to be measured according to a set temperature range and temperature step at each temperature, and use the equivalent circuit model to obtain a test curve of the total capacitance of the optoelectronic device varying with the angular frequency, so as to obtain the characteristic frequencies at different temperatures;

[0037] A linear fitting module, configured to linearly fit the characteristic frequencies at different temperatures to obtain a straight-line slope;

[0038] A data calculation module, configured to obtain the activation energy and capture interface of the optoelectronic device according to the straight-line slope, and characterize the interface defects of the optoelectronic device according to the activation energy and capture interface.

[0039] Further, the characteristic frequency acquisition module includes:

[0040] An environmental parameter setting unit, configured to set the DC bias voltage across the optoelectronic device to be measured, and the temperature range and temperature step in a lightless condition, where the temperature is Fahrenheit temperature;

[0041] A characteristic frequency calculation unit, configured to obtain the characteristic frequencies at different temperatures, including:

[0042] A capacitance detection sub-unit, configured to, at each temperature, under the set DC bias voltage across the optoelectronic device to be measured, vary the angular frequency ω of the AC voltage across the optoelectronic device to be measured, and use the equivalent circuit model to obtain a C-ω / 2π curve of the total capacitance of the optoelectronic device varying with the angular frequency, so as to obtain the total capacitance C0 corresponding to when the angular frequency of the AC voltage approaches infinity;

[0043] A characteristic frequency calculation sub-unit, configured to draw a ωdC / dω-ω / 2π curve according to the C-ω / 2π curve and the total capacitance C0 corresponding to when the angular frequency of the AC voltage approaches infinity, and the angular frequency at the extreme point of the ωdC / dω-ω / 2π curve is the characteristic frequency ω corresponding to the temperature p 。

[0044] Further, the linear fitting module is configured to fit the ln(ω p / T 2 )-1000 / T straight line according to each temperature T and the corresponding characteristic frequency, and calculate the straight-line slope S;

[0045] Obtaining the activation energy and capture interface of the optoelectronic device according to the straight-line slope includes:

[0046] The data calculation module is configured to obtain the activation energy E based on the theoretical relationship between ω p and temperature T, and the straight-line slope Sa , the intercept on the ln(ω p / T 2 ) - 1000 / T straight line corresponding to ln(ω p / T 2 ) axis is the capture interface σ n .

[0047] Advantages of the present invention:

[0048] 1. During the detection process, an equivalent circuit model of the optoelectronic device to be measured is established without damaging the optoelectronic device. Testing is carried out on the basis of ensuring the integrity of the device, accurately measuring the activation energy and capture interface to characterize the interface defects, and new interfaces or defects can be avoided from being introduced;

[0049] 2. At different temperatures, multiple groups of data are obtained through testing, making the calculation results closer to the actual situation. The activation energy can be calculated relatively simply without complex operations;

[0050] 3. The range of the DC bias voltage is determined through the CV curve obtained by testing, which can ensure that the defect energy level coincides with the Fermi energy level to meet the testing requirements;

[0051] 4. By performing a temperature scan at a set DC bias voltage, the direction of the defect type is determined. According to different defect types, the temperature range of the characteristic frequency is confirmed. Within this temperature range, the activation energy and capture interface are more accurately measured to characterize the interface defects of the optoelectronic device.

[0052] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can be made obvious from the description, or understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the content specifically pointed out in the description and the drawings. Description of the Drawings

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0054] Figure 1 It is a flowchart of a method for characterizing optoelectronic device interface defects shown in an embodiment of the present application;

[0055] Figure 2 It is a schematic diagram of a solar cell structure shown in an embodiment of the present application;

[0056] Figure 3 The C-ω / 2π and ωdC / dω-ω / 2π curve graphs shown in an embodiment of the present application;

[0057] Figure 4 The ln(ω p / T 2 ) - 1000 / T straight line obtained by fitting shown in an embodiment of the present application;

[0058] Figure 5 The structural schematic diagram of the optoelectronic device interface defect characterization device shown in another embodiment of the present application.

[0059] Reference numerals:

[0060] 1 - Back Ti / Al metal; 2 - Back n-type polysilicon; 3 - Intermediate n-type substrate; 4 - Front p-type polysilicon; 5 - Metal electrode; 6 - NAOS or thermal oxide thin film passivation layer; 7 - PE oxide layer; 8 - SiNx passivation layer. Detailed implementation manners

[0061] The preferred embodiments of the present invention will be specifically described below in conjunction with the drawings, wherein the drawings form a part of the present application and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0062] As Figure 1 shown, a specific embodiment of the present invention discloses an optoelectronic device interface defect characterization method, including:

[0063] S10. Establish an equivalent circuit model of the optoelectronic device to be measured;

[0064] Specifically, the optoelectronic device to be measured includes a solar cell or a photodetector. In this embodiment, the solar cell is taken as an example for illustration. As Figure 2 shown, the solar cell structure sequentially stacks the back Ti / Al metal 1, the back n-type polysilicon 2, the intermediate n-type substrate 3, the front p-type polysilicon 4 and the metal electrode 5. By non-destructively detecting the interface defects of different passivation layers or without passivation layers, the distribution of defects can be obtained without damage, which is convenient for analyzing the internal factors of the performance of the battery or detector, and at the same time, the passivation effect of different passivation layers on the device can be tested.

[0065] Specifically, the solar cell sample in this embodiment can be generated according to the following steps:

[0066] Grow the passivation layer NAOS or the thermal oxide thin film passivation layer 6 on both sides of the intermediate n-type substrate 3, and the control group grows different passivation layers (including not growing the passivation layer);

[0067] Then, the backside n-type polysilicon 2 is deposited on both sides, and after opening holes on the front side, the front-side p-type polysilicon 4 is deposited, both with in-situ doping;

[0068] After that, after opening holes in the front-side p-type polysilicon 4, a PE oxide layer 7 is grown on the front side as passivation;

[0069] Subsequently, a SiNx passivation layer 8 is grown and photolithographically opened. After depositing Ti / Al metal 1 on the back side and depositing metal electrodes 5 on the front side, the front-side metal is stripped.

[0070] In the optoelectronic device tested in this embodiment, both the front-side p-type polysilicon 4 and the backside n-type polysilicon 2 have high doping concentrations, while the doping concentration of the middle n-type substrate 3 is relatively low. Therefore, the depletion region is basically all located in the substrate (when establishing the equivalent circuit model, since the depletion layer is inside the substrate, but the properties of the region that becomes the depletion layer and the substrate region are very different, so the two are discussed separately), and energy band bending also occurs in this region.

[0071] In the test, first, I-V tests (i.e., voltage-current volt-ampere tests) are performed on the test samples for sample screening. Specifically, samples with an area of 5*5 mm2 can be selected. More specifically, the sample size mainly affects leakage current. The larger the area, the greater the leakage current. If the leakage current is large, the C-V test at high frequencies will be inaccurate. Therefore, devices with a moderate area are generally selected for testing, as long as it is ensured that the leakage current has little impact on the capacitance C test within the selected test range. If the sample area is too small, it is difficult to align the probes during contact. Specifically, for samples with a leakage current in the nA level, at a frequency of 1 MHz, the leakage current has little impact on the capacitance test (it will affect all capacitances, including the depletion layer capacitance and the substrate capacitance), and it can meet the admittance spectroscopy test conditions.

[0072] Specifically, an equivalent circuit model of the optoelectronic device to be measured is established, and the equivalent circuit model is expressed as:

[0073]

[0074] where C is the total capacitance, e p is the emission rate of holes, β is the first constant, ω is the angular frequency of the alternating voltage, and C0 is the total capacitance corresponding to when the angular frequency of the alternating voltage approaches infinity.

[0075] Specifically, under the condition of setting the temperature and the DC bias voltage, the total capacitance C is tested as it changes with the angular frequency ω of the DC bias voltage at both ends of the optoelectronic device to be measured. When the change rate of the total capacitance C reaches the maximum value, the defect energy level coincides with the Fermi energy level, that is, the characteristic frequency ω p = e p .

[0076] S20. Under the set DC bias voltage, according to the set temperature range and temperature step, at each temperature, vary the angular frequency of the AC voltage across the optoelectronic device under test, and use the equivalent circuit model to obtain the test curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtain the characteristic frequencies at different temperatures;

[0077] Specifically, under lightless conditions, set the DC bias voltage across the optoelectronic device under test, the temperature range and the temperature step, and the temperature is in Fahrenheit;

[0078] Setting the DC bias voltage across the optoelectronic device under test includes:

[0079] At room temperature, set the initial DC bias voltage and the initial DC bias voltage step; specifically, the initial DC bias voltage is from -3V to +3V, and the initial DC bias voltage step is 30mV;

[0080] At each initial DC bias voltage, test the total capacitance C and the initial DC bias voltage to obtain the C-V curve, and determine the range of the DC bias voltage according to the C-V curve;

[0081] Specifically, during the process of testing the total capacitance C and the initial DC bias voltage, when the interface in the substrate changes from majority carrier accumulation to majority carrier depletion and then to inversion until the minority carrier concentration is equal to the majority carrier concentration inside the substrate, the capacitance C changes rapidly with the DC bias voltage V. In this process, there will be a coincidence of the defect energy level and the Fermi level. When the characteristic frequency ω p =e p At this time, the change rate of the capacitance C reaches the maximum value. e p is the hole emission rate, so this voltage range is mainly selected for testing. Specifically, the injection of carriers in the semiconductor will affect the change of the carrier concentration in the semiconductor. Doped semiconductors all have carriers. For example, for a p-type semiconductor, holes are the majority carriers and electrons are the minority carriers. Majority carrier accumulation means injecting holes into the p-type semiconductor, and majority carrier depletion means injecting a small amount of electrons into the p-type semiconductor. When too many electrons are injected, the p-type semiconductor will become an n-type semiconductor, that is, an inversion occurs. More specifically, defects can capture electrons, and the energy of the captured electrons is the defect energy level.

[0082] Within the DC bias voltage range, set the DC bias voltage step; specifically, in this embodiment, the DC bias voltage range is from -1V to 1V, and the DC bias voltage step is 20mV;

[0083] At each DC bias voltage, by varying the angular frequency ω of the AC voltage across the optoelectronic device under test, C-ω / 2π curves at different DC bias voltages are obtained. Based on the C-ω / 2π curves at different DC bias voltages, the DC bias voltage across the optoelectronic device under test is set. Specifically, the DC bias voltage value at which the capacitance C varies most significantly with the angular frequency ω is selected. In this embodiment, the DC bias voltage across the optoelectronic device under test is set to -0.2V.

[0084] The setting of the temperature range and temperature step includes:

[0085] At the set DC bias voltage of -0.2V, an initial temperature range and an initial temperature step are set; specifically, the initial temperature range is 10K to 300K, and the initial temperature step is 30K;

[0086] By varying the angular frequency ω of the AC voltage across the optoelectronic device under test, C-ω / 2π curves of the total capacitance of the optoelectronic device varying with the angular frequency at each initial temperature are obtained;

[0087] Based on the C-ω / 2π curves of the total capacitance of the optoelectronic device varying with the angular frequency at each initial temperature, the temperature range is determined, and the temperature step is set based on the temperature range; specifically, scanning is performed within the initial temperature range and initial temperature step. Based on the different temperatures at which the characteristic frequency appears, the temperature range and temperature step for the test are determined. Specifically, in this embodiment, the sample selected shows a characteristic frequency between 150k and 210k. Therefore, the temperature range is selected as 150k to 210k, and the temperature step is set to 20K.

[0088] Specifically, obtaining the characteristic frequencies at different temperatures includes:

[0089] At each temperature, at the set DC bias voltage across the optoelectronic device under test, by varying the angular frequency ω of the AC voltage across the optoelectronic device under test, using the equivalent circuit model, C-ω / 2π curves of the total capacitance of the optoelectronic device varying with the angular frequency are obtained, and the total capacitance C0 corresponding to when the angular frequency of the AC voltage approaches infinity is obtained; specifically, in this embodiment, the amplitude of the AC voltage is 50mV, and the range of the AC voltage frequency ω / 2π is 1kHz - 1MHz. By varying the angular frequency ω of the voltage, the variation curve of the optoelectronic device C is tested, as Figure 3 shown. A C-ω / 2π curve is plotted with the frequency ω / 2π as the abscissa and the battery capacitance C as the right ordinate. Under small-signal AC voltage conditions, when the angular frequency is much lower than the characteristic frequency ω p the capacitance is equal to C d and when the angular frequency is much higher than the characteristic frequency ω p the capacitance is equal to C g Therefore, by measuring the relationship between the battery capacitance C and the frequency ω / 2π, the characteristic frequency ω can be confirmedp (Also known as the inflection point frequency).

[0090] Specifically, the magnitude of the defect concentration can be obtained from the C-ω / 2π curve and is expressed as:

[0091] ΔC = C max - C min

[0092] where the larger ΔC is, the larger the defect concentration is, C max is the maximum value of the measured battery capacitance C, and C min is the minimum value of the measured battery capacitance C.

[0093] Specifically, as Figure 3 shown, according to the C-ω / 2π curve and the total capacitance C0 corresponding when the angular frequency of the AC voltage approaches infinity, the ωdC / dω-ω / 2π curve is plotted according to formula (1), and the angular frequency at the extreme point of the ωdC / dω-ω / 2π curve is the characteristic frequency ω p corresponding at the temperature, and at this time the emission rate e p of the electrons captured by the defect energy level is p = ω

[0094] The theoretical relationship between the ω p and the temperature T is obtained by the following formula:

[0095]

[0096] where e p is the emission rate of holes, σ is the defect capture area, v th is the carrier movement speed and is proportional to T 1 / 2 , N v is the valence band density of states and is proportional to T 3 / 2 , E a is the activation energy, k is the Boltzmann constant, and α is the second constant.

[0097] S30. According to the characteristic frequencies at different temperatures, the slope of the straight line is obtained by linear fitting;

[0098] According to each temperature T and the corresponding characteristic frequency, the ln(ω p / T 2 )-1000 / T straight line is fitted, and the slope S of the straight line is calculated; specifically, at a set DC bias voltage, the above tests are repeated to obtain the characteristic frequency corresponding to each temperature. As Figure 4 shown, with 1000 / T as the abscissa and ln(ω p / T 2 ) as the ordinate, the ln(ω p / T2 ) - 1000 / T straight line, and calculate the slope S of the straight line.

[0099] S40. According to the slope of the straight line, obtain the activation energy and capture interface of the optoelectronic device, and characterize the interface defects of the optoelectronic device according to the activation energy and capture interface.

[0100] Specifically, obtaining the activation energy and capture interface of the optoelectronic device according to the slope of the straight line includes:

[0101] Based on the p theoretical relationship between ω a and temperature T, and the slope S of the straight line, obtain the activation energy E p where the intercept on the ln(ω 2 / T p / T 2 ) - 1000 / T straight line corresponding to the ln(ω n ) axis is the capture interface σ

[0102] Specifically, obtain the activation energy E from the slope S of the straight line a expressed as:

[0103] E a = 1000k × S

[0104] where k is the Boltzmann constant.

[0105] Specifically, the activation energy corresponds to the defect energy level, and the activation energy E a is expressed as:

[0106] E a = E t - E v

[0107] where E t is the defect energy level, E v is the valence band energy level, and the valence band energy level of the optoelectronic device is a known parameter.

[0108] Specifically, without damaging the battery structure, through the obtained activation energy, capture interface and defect concentration, the closer the defect energy level is to the center of the energy band, the worse the passivation effect, the smaller the capture interface, and the lower the defect concentration, the better the passivation effect. By comparing the passivation effects of different passivation layers, the interface defects corresponding to different passivation layers can be characterized.

[0109] Another specific embodiment of the present invention discloses a method for characterizing interface defects of an optoelectronic device. This embodiment is different from the equivalent circuit model established in the above-mentioned embodiment S10, specifically as follows:

[0110] S10. Establish an equivalent circuit model of the optoelectronic device to be measured;

[0111] Specifically, an equivalent circuit model of the optoelectronic device to be tested is established, and the equivalent circuit model is expressed as:

[0112]

[0113] where G is the total capacitance, e p is the emission rate of holes, β is the first constant, and ω is the angular frequency of the AC voltage.

[0114] Specifically, under the condition of set temperature and DC bias voltage, the total conductance G is tested as it changes with the angular frequency ω of the DC bias voltage across the optoelectronic device to be tested. When the total conductance G reaches the maximum value, the defect energy level coincides with the Fermi energy level, that is, the characteristic frequency ω p = e p .

[0115] To adapt to the equivalent circuit model in S10 of this embodiment, corresponding adjustments are made in S20 as follows:

[0116] S20. Under the set DC bias voltage, according to the set temperature range and temperature step, at each temperature, the angular frequency of the AC voltage across the optoelectronic device to be tested is changed, and using the equivalent circuit model, the test curve of the total conductance of the optoelectronic device changing with the angular frequency is obtained, and the characteristic frequencies at different temperatures are obtained;

[0117] Specifically, under the condition of no light, the DC bias voltage across the optoelectronic device to be tested and the temperature range and temperature step are set, and the temperature is in Fahrenheit;

[0118] The setting of the DC bias voltage, the set temperature range and temperature step are the same as the setting process in the above embodiment, and will not be elaborated here;

[0119] Specifically, by changing the angular frequency ω of the AC voltage across the optoelectronic device to be tested, the G-ω / 2π curve of the total conductance of the optoelectronic device changing with the angular frequency at each initial temperature is obtained; the frequency corresponding to the peak point of the conductance G is ω p ; specifically, in this embodiment, the amplitude of the AC voltage is 50 mV, and the range of the AC voltage frequency ω / 2π is 1 kHz - 1 MHz. By changing the angular frequency ω of the voltage, the change curve of the battery conductance G is tested. Under the condition of small-signal AC voltage, the frequency corresponding to the peak point of the conductance G is ω p (also called the inflection point frequency).

[0120] S30. According to the characteristic frequencies at different temperatures, a linear fit is performed to obtain the slope of the straight line; the process of obtaining the slope of the straight line by linear fit is the same as that in the above embodiment, and will not be elaborated here;

[0121] S40. Obtain the activation energy and capture interface of the optoelectronic device according to the slope of the straight line, and characterize the interface defects of the optoelectronic device based on the activation energy and capture interface. The process of obtaining the activation energy and capture interface of the optoelectronic device is the same as that in the above embodiments and will not be elaborated here.

[0122] As Figure 5 shown, another specific embodiment of the present invention discloses an optoelectronic device interface defect characterization device, including:

[0123] A model establishment module 10 for establishing an equivalent circuit model of the optoelectronic device to be measured;

[0124] A characteristic frequency acquisition module 20 for, under a set DC bias voltage, according to a set temperature range and temperature step size, at each temperature, varying the angular frequency of the AC voltage across the optoelectronic device to be measured, and using the equivalent circuit model to obtain a test curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtaining characteristic frequencies at different temperatures;

[0125] The characteristic frequency acquisition module 20 includes:

[0126] An environmental parameter setting unit 201 for setting the DC bias voltage across the optoelectronic device to be measured and the temperature range and temperature step size under lightless conditions, and the temperature is in Fahrenheit;

[0127] A characteristic frequency calculation unit 202 for obtaining characteristic frequencies at different temperatures, including:

[0128] A capacitance detection sub-unit for, at each temperature, under the set DC bias voltage across the optoelectronic device to be measured, by varying the angular frequency ω of the AC voltage across the optoelectronic device to be measured, and using the equivalent circuit model to obtain a C-ω / 2π curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtaining the total capacitance C0 corresponding to when the angular frequency of the AC voltage approaches infinity;

[0129] A characteristic frequency calculation sub-unit for, according to the C-ω / 2π curve and the total capacitance C0 corresponding to when the angular frequency of the AC voltage approaches infinity, plotting a ωdC / dω-ω / 2π curve, and the angular frequency at the extreme point of the ωdC / dω-ω / 2π curve is the characteristic frequency ω corresponding to the temperature p .

[0130] A linear fitting module 30 for linearly fitting to obtain the slope of a straight line according to the characteristic frequencies at different temperatures; specifically, the linear fitting module is used to, according to each temperature T and the corresponding characteristic frequency, fit to obtain a straight line of ln(ω p / T 2 )-1000 / T, and calculate the slope S of the straight line

[0131] The data calculation module 40 is configured to obtain the activation energy and the capture interface of the optoelectronic device according to the slope of the straight line, and characterize the interface defects of the optoelectronic device according to the activation energy and the capture interface. Specifically, the data calculation module is configured to obtain the activation energy E based on the theoretical relationship between ω p and temperature T, and the slope S of the straight line a , where the intercept on the ln(ω p / T 2 ) axis corresponding to the ln(ω p / T 2 ) - 1000 / T straight line is the capture interface σ n .

[0132] Those skilled in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

[0133] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for characterizing interface defects of optoelectronic devices, characterized in that, including: Establish an equivalent circuit model of the optoelectronic device to be measured; Under a set DC bias voltage, according to the set temperature range and temperature step, at each temperature, vary the angular frequency of the AC voltage across the optoelectronic device to be measured, and use the equivalent circuit model to obtain the test curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtain the characteristic frequencies at different temperatures; According to the characteristic frequencies at different temperatures, linearly fit to obtain the slope of the straight line; According to the slope of the straight line, obtain the activation energy and capture interface of the optoelectronic device, and characterize the interface defects of the optoelectronic device according to the activation energy and capture interface; Under lightless conditions, set the DC bias voltage across the optoelectronic device to be measured and the temperature range and temperature step, and the temperature is Fahrenheit temperature; The obtaining of the characteristic frequencies at different temperatures includes: At each temperature, under the DC bias voltage set across the optoelectronic device to be measured, by varying the angular frequency of the AC voltage across the optoelectronic device to be measured , using the equivalent circuit model, obtain the curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtain the total capacitance corresponding to when the angular frequency of the AC voltage approaches infinity ; According to the total capacitance corresponding to when the angular frequency of the curve and the AC voltage approaches infinity , plot the curve, and the angular frequency at the extreme point of the curve is the characteristic frequency corresponding to the temperature ; Among them, the slope of the straight line obtained by linear fitting includes: fitting according to each of the temperatures T and the corresponding characteristic frequencies to obtain a straight line and calculating the slope of the straight line ; The obtaining of the activation energy and capture interface of the optoelectronic device according to the slope of the straight line includes: Based on the theoretical relationship with temperature T, and the slope of the straight line the activation energy is obtained , the intercept of the straight line on the axis is the trapping interface .

2. The method for characterizing the interface defects of an optoelectronic device according to claim 1, wherein: Establish an equivalent circuit model of the optoelectronic device to be measured, and the equivalent circuit model is expressed as: ； Among them, is the total capacitance, is the emission rate of holes, is the first constant, is the angular frequency of the alternating voltage, is the total capacitance corresponding to when the angular frequency of the alternating voltage approaches infinity.

3. The method for characterizing the interface defects of optoelectronic devices according to claim 1, wherein The following formula is used to obtain the and temperature theoretical relationship: ； Among them, is the emission rate of holes, is the defect capture area, is the carrier movement speed and is proportional to is the valence band density of states and is proportional to is the activation energy, is the Boltzmann constant, is the second constant.

4. The method for characterizing the interface defects of an optoelectronic device according to claim 1, wherein: Setting the DC bias voltage includes: At room temperature, set the initial DC bias voltage and the initial DC bias voltage step; At each initial DC bias voltage, measure the total capacitance C and the initial DC bias voltage, obtain the C-V curve, and determine the range of the DC bias voltage according to the C-V curve; Within the range of the DC bias voltage, set the DC bias voltage step; At each DC bias voltage, by varying the angular frequency of the AC voltage across the optoelectronic device under test , the curves at different DC bias voltages are obtained. Based on the curves at different DC bias voltages, the DC bias voltage is set.

5. The method for characterizing the interface defects of an optoelectronic device according to claim 4, wherein: The setting of the temperature range and temperature step includes: Under the set DC bias voltage, set the initial temperature range and the initial temperature step; By varying the angular frequency of the AC voltage across the optoelectronic device to be measured , obtain the curve of the total capacitance of the optoelectronic device varying with the angular frequency at each initial temperature; Determine the temperature range according to the curve of the total capacitance of the optoelectronic device varying with the angular frequency at each of the initial temperatures, and set the temperature step according to the temperature range. ​ 6. An interface defect characterization device for optoelectronic devices, characterized in that, including: A model establishment module for establishing an equivalent circuit model of the optoelectronic device to be measured; A characteristic frequency acquisition module for, under a set DC bias voltage, according to the set temperature range and temperature step, at each temperature, vary the angular frequency of the AC voltage across the optoelectronic device to be measured, and use the equivalent circuit model to obtain the test curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtain the characteristic frequencies at different temperatures; A linear fitting module for linearly fitting according to the characteristic frequencies at different temperatures to obtain the slope of the straight line; A data calculation module for, according to the slope of the straight line, obtaining the activation energy and capture interface of the optoelectronic device, and characterizing the interface defects of the optoelectronic device according to the activation energy and capture interface; The characteristic frequency acquisition module includes: An environmental parameter setting unit for, under lightless conditions, setting the DC bias voltage across the optoelectronic device to be measured and the temperature range and temperature step, and the temperature is Fahrenheit temperature; A characteristic frequency calculation unit for obtaining the characteristic frequencies at different temperatures, including: A capacitance detection sub-unit, which is configured to, at each temperature and under a set DC bias voltage across the optoelectronic device to be measured, vary the angular frequency of the AC voltage across the optoelectronic device to be measured , and utilize the equivalent circuit model to obtain the curve of the total capacitance of the optoelectronic device varying with the angular frequency, and obtain the total capacitance corresponding to when the angular frequency of the AC voltage approaches infinity ; A characteristic frequency calculation subunit, configured to, according to the curve and the total capacitance corresponding when the angular frequency of the AC voltage approaches infinity, plot a curve, where the angular frequency at the extreme point of the curve is the characteristic frequency corresponding to the temperature ; The linear fitting module is used to fit a straight line based on each temperature T and the corresponding characteristic frequency, and calculate the slope of the straight line; The obtaining of the activation energy and capture interface of the optoelectronic device according to the slope of the straight line includes: The data calculation module is used to based on the theoretical relationship with the temperature T, and the slope of the straight line to obtain the activation energy , the intercept of the straight line corresponding to on the axis is the capture interface .

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