Photoelectric effect measurement system

Abstract

A photoelectric effect measurement system belongs to the field of semiconductor technology. The present invention aims at the problem that the current photoelectric effect measurement system uses a filter wheel to filter light of different wavelengths, and the test range is narrow and the test flexibility is poor. It includes a full-spectrum light generation module, which uses a full-spectrum LED lamp bead to emit full-spectrum light, and forms parallel light through a collimating lens; a wavelength selection module, which uses a prism to refract the incident parallel light to obtain a single wavelength light beam; the single wavelength light beam is incident on a semiconductor sample; the prism is controlled by an angle servo mechanism to rotate the target angle to change the wavelength of the output light beam; a weak voltage and current detection module, which is used to detect the short-circuit current and open-circuit voltage of the semiconductor sample when different single wavelength light beams are incident, and convert them into digital signals for output. The present invention is used for semiconductor PN junction photoelectric effect measurement.

Description

Technical Field

[0001] The invention relates to a photoelectric effect measurement system and belongs to the technical field of semiconductors. Background Art

[0002] The photoelectric properties of a semiconductor PN junction refer to the phenomenon in which, when light strikes the junction, the light energy is absorbed by the semiconductor material, exciting valence band electrons to the conduction band, forming electron-hole pairs. The electron-hole pairs are then separated into the P and N regions by the built-in electric field within the PN junction, creating a voltage difference across the junction, generating a photocurrent. The photocurrent is proportional to the light intensity; the stronger the light, the greater the photocurrent. This principle is widely used in solar cells. By measuring the photoelectric effect curve of the PN junction, key parameters such as solar cell conversion efficiency and output power can be accurately assessed, ensuring that solar cell performance meets established standards and providing an important technical basis for photovoltaic system design. Long-term monitoring of the photovoltaic IV curve also facilitates accurate fault analysis of photovoltaic system electrical performance and understands performance changes over long-term operation. Different materials have different light sensitivities, primarily manifested in differences in light absorption at different wavelengths. Measuring the photoelectric effect curve under different wavelengths of light can provide guidance for improving solar cell efficiency.

[0003] Current systems for measuring the photoelectric effect of semiconductor PN junctions primarily use a filter wheel to filter light of different wavelengths. The system then measures the open-circuit voltage and short-circuit current of the PN junction under light of varying wavelengths and intensities to obtain the PN junction's photoelectric effect curve. This method, based on the wavelength of light transmitted, is determined by the color of the filters on the filter wheel. Consequently, it can only measure the PN junction's photoelectric effect curve under a limited number of wavelengths, resulting in limited flexibility and an inability to accurately determine the wavelength to which the PN junction is sensitive. Summary of the Invention

[0004] Aiming at the problems that the current photoelectric effect measurement system uses a filter wheel to filter light of different wavelengths, resulting in a narrow test range and poor test flexibility, the present invention provides a photoelectric effect measurement system.

[0005] An electric effect measurement system of the present invention comprises:

[0006] Full-spectrum light generating module, used to use full-spectrum LED lamp beads to emit full-spectrum light, and form parallel light through the collimating lens;

[0007] A wavelength selection module, which uses a prism to refract the incident parallel light to obtain a single wavelength beam; the single wavelength beam is incident on the semiconductor sample; the prism is rotated to a target angle value by an angle servo mechanism to change the wavelength of the output beam;

[0008] Weak voltage and current detection module, used to detect the short-circuit current and open-circuit voltage of semiconductor samples when different single wavelength light beams are incident, and convert them into digital signal output;

[0009] The single-chip microcomputer control module is used to calculate the target rotation angle of the prism according to the detection instruction and transmit it to the angle servo mechanism; it is also used to calculate the target driving current according to the detection instruction, generate a PWM signal to control the LED light source driver module of the full-spectrum light generation module to output the driving current to load the full-spectrum LED lamp beads, so that the full-spectrum LED lamp beads emit full-spectrum light with the target light intensity; and simultaneously receive the short-circuit current and open-circuit voltage digital signals output by the weak voltage and current detection module;

[0010] The wavelength selection module also includes a servo angle detection mechanism for detecting an actual rotation angle output by the angle servo mechanism;

[0011] The angle servo mechanism performs closed-loop calculation based on the difference between the actual rotation angle and the target rotation angle value, thereby realizing rotation control of the prism's target rotation angle value;

[0012] The angle servo mechanism includes a servo control module, a motor drive module and a motor; the servo angle detection mechanism includes an angle transmission mechanical structure and an absolute position encoder; the prism is arranged on the angle transmission mechanical structure;

[0013] The servo control module receives the rotation angle target value output by the single-chip control module and generates a drive control signal to the motor drive module. The motor drive module controls the motor to rotate and drive the prism to rotate. The actual rotation angle of the motor is transmitted through the angle transmission mechanical structure and then input into the absolute position encoder. The absolute position encoder converts the actual rotation angle into a digital signal and inputs it into the servo control module.

[0014] The servo control module performs closed-loop calculation based on the difference between the actual rotation angle and the target rotation angle value and performs closed-loop control on the motor.

[0015] According to the photoelectric effect measurement system of the present invention, the LED light source driving module includes a constant current driving control module and a current detection module. The constant current driving control module is used to generate a driving current according to the PWM signal output by the single-chip control module and load it onto the full-spectrum LED lamp bead; the current detection module is used to detect the actual current value of the full-spectrum LED lamp bead; the constant current driving control module adjusts the output driving current according to the difference between the driving current and the actual current value, thereby realizing closed-loop control of the full-spectrum LED lamp bead.

[0016] According to the photoelectric effect measurement system of the present invention, the servo control module includes an encoder readout module, a PID controller and an adder.

[0017] The encoder readout module is used to read the actual rotation angle in the form of digital signal output by the absolute position encoder;

[0018] The adder receives the rotation angle target value transmitted by the single-chip control module and subtracts the actual rotation angle in the form of a digital signal to obtain the angle increment value. The PID controller calculates the drive control signal and sends it to the motor drive module.

[0019] According to the photoelectric effect measurement system of the present invention, the parallel light emitted by the collimating lens is incident on the prism after being selected by the rectangular hollow on the light shielding plate.

[0020] According to the photoelectric effect measurement system of the present invention, the semiconductor sample is arranged in a dark chamber, and a rectangular slit is provided in the dark chamber to allow part of the single wavelength light beam to be incident on the semiconductor sample.

[0021] According to the photoelectric effect measurement system of the present invention, the weak voltage and current detection module includes a current-voltage conversion circuit and a weak voltage detection circuit;

[0022] The current-voltage conversion circuit includes a switch S1, a switch S2, a resistor R1, a resistor R2, and a capacitor C1; the weak voltage detection circuit includes a single-pole double-throw switch S3, a resistor R3, a capacitor C2, a resistor R4, a resistor R5, a resistor R6, a JFET operational amplifier AMP1, a resistor R7, a capacitor C3, a resistor R8, a resistor R9, a resistor R10, a capacitor C4, and an operational amplifier AMP2;

[0023] One end of the semiconductor sample is connected to one end of a switch S1, the other end of the switch S1 is connected to one end of a switch S2, the other end of the switch S2 is connected to the other end of the semiconductor sample, and a resistor R1 is connected in parallel with the switch S2; the other end of the switch S1 is also connected to one end of a resistor R2, the other end of the resistor R2 is connected to one end of a capacitor C1, the other end of the capacitor C1 is grounded and connected to the other end of S2;

[0024] The other end of resistor R2 is connected to input terminal a of single-pole double-throw switch S3; one end of the semiconductor sample is connected to one end of resistor R3, and the other end of resistor R3 is connected to input terminal b of single-pole double-throw switch S3; the other end of resistor R3 is grounded via capacitor C2; one end of single-pole double-throw switch S3 is set corresponding to input terminal a and input terminal b, and the other end is connected to the non-inverting input terminal of JFET op amp AMP1 via resistor R6, and the inverting input terminal of JFET op amp AMP1 is grounded via resistor R4; the inverting input terminal of JFET op amp AMP1 is connected to the output terminal via resistor R5; the output terminal of JFET op amp AMP1 is connected to one end of resistor R7, and the other end of resistor R7 is grounded via capacitor C3; the other end of resistor R7 is connected to the inverting input terminal of op amp AMP2 via resistor R8, and the non-inverting input terminal of op amp AMP2 is grounded via resistor R9;

[0025] The other end of the resistor R7 is connected to the output end of the operational amplifier AMP2 via the resistor R10, and the inverting input end of the operational amplifier AMP2 is connected to the output end;

[0026] When switch S1 is closed and switch S2 is open, the single-pole double-throw switch S3 is connected to input terminal a; when switch S1 is open and switch S2 is closed, the single-pole double-throw switch S3 is connected to input terminal b;

[0027] The output terminal of the operational amplifier AMP2 outputs analog signals of the short-circuit current and open-circuit voltage of the semiconductor sample.

[0028] According to the photoelectric effect measurement system of the present invention, the weak voltage and current detection module also includes an analog-to-digital conversion circuit for converting the analog signals of the short-circuit current and open-circuit voltage outputted from the output end of AMP2 into digital signals and inputting them into the single-chip control module.

[0029] The beneficial effects of the present invention are as follows: The present invention can be used to measure the photoelectric effect curve of photosensitive materials and includes a circuit control section, an optical section, and a mechanical section. The optical section uses full-spectrum LED lamp beads to emit full-spectrum light, which is then parallelized by a collimating lens. The parallelized light is refracted by a prism to form light of different wavelengths. By rotating the prism angle, light of different wavelengths can be aligned and irradiated onto the test area of ​​the sample. The angle of rotation of the prism is controlled with high precision and high stability by an angle servo mechanism. The weak voltage and current detection module measures the electrical properties of the semiconductor sample, enabling high-precision DC voltage measurement.

[0030] The system of the present invention adopts a wavelength selection module to obtain light beams of different wavelengths, and realizes closed-loop control of the rotation angle of the prism through an angle servo mechanism, which can realize precise adjustment of the wavelength of a continuous light wavelength range; it solves the problems of narrow wavelength test range and low test flexibility in the prior art system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a system block diagram of the photoelectric effect measurement system of the present invention;

[0032] Figure 2 is a block diagram of the circuit and control portion of the photoelectric effect measurement system of the present invention;

[0033] Figure 3 It is a schematic diagram of the implementation method of the prism angle control;

[0034] Figure 4 This is the circuit schematic diagram of the weak voltage and current detection module. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0038] Specific implementation method 1. Combination Figures 1 to 4 As shown, the present invention provides a photoelectric effect measurement system, comprising:

[0039] The full-spectrum light generating module is used to emit full-spectrum light using full-spectrum LED lamp beads 110 and form parallel light through the collimating lens 120;

[0040] The wavelength selection module uses a prism 210 to refract the incident parallel light to obtain a single wavelength beam; the single wavelength beam is incident on the semiconductor sample; the prism 210 is rotated to a target angle value through an angle servo mechanism 220 to change the wavelength of the output beam;

[0041] The weak voltage and current detection module is used to detect the short-circuit current and open-circuit voltage of semiconductor samples when different single wavelength light beams are incident, and convert them into digital signal output.

[0042] The collimated light generated by the collimating lens 120 can be partially incident on the prism 210 using a light shield. The full-spectrum light is refracted by the prism 210, creating light of varying wavelengths that is incident on the semiconductor sample. The angle servo mechanism 220 continuously changes the wavelength of light incident on the semiconductor sample by adjusting the angle of the prism 210. The weak voltage and current detection module measures the relatively weak open-circuit voltage and short-circuit current of the semiconductor sample, thereby generating a photoelectric effect curve for the semiconductor sample at different wavelengths.

[0043] Further, combined Figure 1 and Figure 2As shown, this embodiment also includes a single-chip microcomputer control module, which is used to calculate the target value of the rotation angle of the prism 210 according to the detection instruction and transmit it to the angle servo mechanism 220; it is also used to calculate the target value of the driving current according to the detection instruction, generate a PWM signal to control the LED light source driving module 130 of the full-spectrum light generating module to output the driving current to be loaded onto the full-spectrum LED lamp bead 110, so that the full-spectrum LED lamp bead 110 emits full-spectrum light of the target light intensity; and at the same time receive the digital signals of the short-circuit current and open-circuit voltage output by the weak voltage and current detection module.

[0044] This embodiment can adopt two human-computer interaction approaches. The single-chip control module can transmit detection instructions through the human-computer interaction module or the host computer. The single-chip control module can be connected to the host computer through a USB interface. The single-chip control module generates a PWM signal to control the LED light source driver module 130 to generate a controllable drive current loaded on the full-spectrum LED lamp bead 110, which can achieve the purpose of controlling the light intensity. The short-circuit current and open-circuit voltage signals received by the single-chip control module, the angle signal of the prism, and the current of the full-spectrum LED lamp bead 110 can be transmitted to the human-computer interaction module or the host computer and displayed through a display or other device; the host computer can also store the received data.

[0045] Combine Figure 2 As shown, in this embodiment, the LED light source driving module 130 includes a constant current driving control module and a current detection module. The constant current driving control module is used to generate a driving current according to the PWM signal output by the single-chip control module and load it onto the full-spectrum LED lamp bead 110; the current detection module is used to detect the actual current value of the full-spectrum LED lamp bead 110; the constant current driving control module adjusts the output driving current according to the difference between the driving current and the actual current value, thereby realizing closed-loop control of the full-spectrum LED lamp bead 110.

[0046] The constant current drive control module and the current detection module detect the current of the full-spectrum LED lamp bead 110 in real time to achieve accurate closed-loop control of the current.

[0047] Going further, combined Figure 2 As shown, the wavelength selection module further includes a servo angle detection mechanism 230 for detecting the actual rotation angle output by the angle servo mechanism 220;

[0048] The angle servo mechanism 220 performs closed-loop calculation based on the difference between the actual rotation angle and the target rotation angle value, thereby realizing rotation control of the prism 210 to the target rotation angle value.

[0049] Combine Figure 3As shown, the angle servo mechanism 220 includes a servo control module, a motor drive module and a motor; the servo angle detection mechanism 230 includes an angle transmission mechanical structure 231 and an absolute position encoder 232; the prism 210 is set on the angle transmission mechanical structure 231;

[0050] The servo control module receives the rotation angle target value output by the single-chip control module and generates a drive control signal to the motor drive module. The motor drive module controls the motor to rotate and drive the prism 210 to rotate. The actual rotation angle of the motor is transmitted through the angle transmission mechanism 231 and then input to the absolute position encoder 232. The absolute position encoder 232 converts the actual rotation angle into a digital signal and inputs it to the servo control module.

[0051] The servo control module performs closed-loop calculation based on the difference between the actual rotation angle and the target rotation angle value and performs closed-loop control on the motor.

[0052] The angle servo mechanism 220 takes the rotation angle target value input by the single chip control module as the target and implements high-precision closed-loop control of the motor angle according to the angle signal of the absolute position encoder 232.

[0053] The servo control module includes an encoder readout module, a PID controller and an adder.

[0054] The encoder readout module is used to read the actual rotation angle in the form of a digital signal output by the absolute position encoder 232;

[0055] The adder receives the rotation angle target value transmitted by the single-chip control module and subtracts the actual rotation angle in the form of a digital signal to obtain the angle increment value. The PID controller calculates the drive control signal and sends it to the motor drive module.

[0056] The PID controller can achieve high-precision and high-stability angle control of the prism, and ultimately ensure that the prism is accurately rotated to the target rotation angle value and remains stable at that angle.

[0057] Combine Figure 1 As shown, in this embodiment, the parallel light emitted from the collimating lens 120 is incident on the prism 210 after passing through the rectangular hollows on the light shielding plate.

[0058] The semiconductor sample is placed in a darkroom with a rectangular slit to allow part of the single wavelength beam to be incident on the semiconductor sample. The wavelength of light is selected by the rotation angle of the prism 210 and the rectangular slit of the darkroom to allow the single wavelength beam to be incident on the surface of the semiconductor sample.

[0059] Going further, combined Figure 3 and Figure 4As shown, the weak voltage and current detection module includes a current-voltage conversion circuit 310 and a weak voltage detection circuit 320;

[0060] The current-to-voltage conversion circuit 310 includes a switch S1, a switch S2, a resistor R1, a resistor R2, and a capacitor C1; the weak voltage detection circuit 320 includes a single-pole double-throw switch S3, a resistor R3, a capacitor C2, a resistor R4, a resistor R5, a resistor R6, a JFET operational amplifier AMP1, a resistor R7, a capacitor C3, a resistor R8, a resistor R9, a resistor R10, a capacitor C4, and an operational amplifier AMP2;

[0061] One end of the semiconductor sample is connected to one end of a switch S1, the other end of the switch S1 is connected to one end of a switch S2, the other end of the switch S2 is connected to the other end of the semiconductor sample, and a resistor R1 is connected in parallel with the switch S2; the other end of the switch S1 is also connected to one end of a resistor R2, the other end of the resistor R2 is connected to one end of a capacitor C1, the other end of the capacitor C1 is grounded and connected to the other end of S2;

[0062] The other end of resistor R2 is connected to input terminal a of single-pole double-throw switch S3; one end of the semiconductor sample is connected to one end of resistor R3, and the other end of resistor R3 is connected to input terminal b of single-pole double-throw switch S3; the other end of resistor R3 is grounded via capacitor C2; one end of single-pole double-throw switch S3 is set corresponding to input terminal a and input terminal b, and the other end is connected to the non-inverting input terminal of JFET op amp AMP1 via resistor R6, and the inverting input terminal of JFET op amp AMP1 is grounded via resistor R4; the inverting input terminal of JFET op amp AMP1 is connected to the output terminal via resistor R5; the output terminal of JFET op amp AMP1 is connected to one end of resistor R7, and the other end of resistor R7 is grounded via capacitor C3; the other end of resistor R7 is connected to the inverting input terminal of op amp AMP2 via resistor R8, and the non-inverting input terminal of op amp AMP2 is grounded via resistor R9;

[0063] The other end of the resistor R7 is connected to the output end of the operational amplifier AMP2 via the resistor R10, and the inverting input end of the operational amplifier AMP2 is connected to the output end;

[0064] When switch S1 is closed and switch S2 is open, the single-pole double-throw switch S3 is connected to input terminal a; when switch S1 is open and switch S2 is closed, the single-pole double-throw switch S3 is connected to input terminal b;

[0065] The output terminal of the operational amplifier AMP2 outputs analog signals of the short-circuit current and open-circuit voltage of the semiconductor sample.

[0066] The JFET op amp AMP1 has very high input impedance and small flicker noise at low frequencies, enabling high-precision DC voltage measurement.

[0067] In this embodiment, resistor R2 is connected to capacitor C1, and resistor R3 is connected to capacitor C2, forming two first-order passive low-pass filters; the non-inverting input terminal of JFET operational amplifier AMP1 is connected to resistor R6, the inverting input terminal is connected to resistor R4 and resistor R5, and the output terminal is connected to resistor R7, forming a non-inverting proportional amplifier circuit; resistor R7 is connected to capacitor C3, resistor R8, and resistor R10, the non-inverting input terminal of operational amplifier AMP2 is connected to resistor R9, the inverting input terminal is connected to resistor R8 and capacitor C4, and the output terminal is connected to resistor R10 and capacitor C4, forming a second-order active low-pass filter.

[0068] When switch S1 is closed and switch S2 is open, resistor R1 is connected to both ends of the semiconductor sample. Since resistor R1 is very small, the current flowing through resistor R1 is approximately the short-circuit current of the semiconductor sample, generating a voltage drop on resistor R1. After being filtered by resistor R2 and capacitor C1, it is input into the weak voltage detection circuit; when switch S2 is closed and switch S1 is open, the open-circuit voltage across the semiconductor sample is measured and filtered by resistor R3 and capacitor C2.

[0069] A single-pole double-throw switch S3 is used to select the output voltage in two situations: connected to input terminals a and b respectively. After the voltage is amplified by the in-phase proportional amplifier circuit, it is input into a second-order active low-pass filter to obtain the final voltage signal.

[0070] In this embodiment, the weak voltage and current detection module also includes an analog-to-digital conversion circuit 330, which is used to convert the analog signals of the short-circuit current and open-circuit voltage output from the output end of AMP2 into digital signals and input them into the single-chip microcomputer control module to realize the electrical characteristics detection of the semiconductor sample.

[0071] The weak voltage detection circuit directly detects the open circuit voltage of the semiconductor sample, and the current-voltage conversion circuit converts the short circuit current of the semiconductor sample into a voltage signal and inputs it to the weak voltage detection circuit to indirectly detect the short circuit current of the semiconductor sample.

[0072] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in conjunction with other described embodiments.

Claims

1. A photoelectric effect measurement system, characterized in that: include: A full-spectrum light generating module, used for emitting full-spectrum light using full-spectrum LED lamp beads (110) to form parallel light through a collimating lens (120); A wavelength selection module uses a prism (210) to refract the incident parallel light to obtain a single wavelength light beam; the single wavelength light beam is incident on a semiconductor sample; the prism (210) is controlled to rotate at a target angle through an angle servo mechanism (220) to change the wavelength of the outgoing light beam; Weak voltage and current detection module, used to detect the short-circuit current and open-circuit voltage of semiconductor samples when different single-wavelength light beams are incident, and convert them into digital signal output; The single-chip computer control module is used to calculate a target rotation angle value of the prism (210) according to a detection instruction, and transmit the target rotation angle value to the angle servo mechanism (220); it is also used to calculate a target drive current value according to the detection instruction, generate a PWM signal to control the LED light source drive module (130) of the full-spectrum light generation module to output a drive current to load onto the full-spectrum LED lamp bead (110), so that the full-spectrum LED lamp bead (110) emits full-spectrum light of a target light intensity; and simultaneously receive digital signals of short-circuit current and open-circuit voltage output by the weak voltage and current detection module; The wavelength selection module also includes a servo angle detection mechanism (230) for detecting an actual rotation angle output by the angle servo mechanism (220); The angle servo mechanism (220) performs closed-loop calculation according to the difference between the actual rotation angle and the target rotation angle value, thereby realizing rotation control of the target rotation angle value of the prism (210); The angle servo mechanism (220) comprises a servo control module, a motor drive module and a motor; the servo angle detection mechanism (230) comprises an angle transmission mechanical structure (231) and an absolute position encoder (232); the prism (210) is arranged on the angle transmission mechanical structure (231); The servo control module receives the rotation angle target value output by the single-chip control module and generates a drive control signal to the motor drive module. The motor drive module controls the motor to rotate to drive the prism (210) to rotate. The actual rotation angle of the motor is transmitted by the angle transmission mechanical structure (231) and then input into the absolute position encoder (232). The absolute position encoder (232) converts the actual rotation angle into a digital signal and inputs it into the servo control module. The servo control module performs closed-loop calculation and closed-loop control of the motor according to the difference between the actual rotation angle and the target rotation angle value; The LED light source driving module (130) comprises a constant current driving control module and a current detection module. The constant current driving control module is used to generate a driving current according to a PWM signal output by the single-chip control module and load it onto the full-spectrum LED lamp bead (110). The current detection module is used to detect the real current value of the full-spectrum LED lamp bead (110). The constant current drive control module adjusts the output drive current according to the difference between the drive current and the real current value, thereby realizing closed-loop control of the full-spectrum LED lamp bead (110); The weak voltage and current detection module comprises a current-voltage conversion circuit (310) and a weak voltage detection circuit (320); The current-voltage conversion circuit (310) comprises a switch S1, a switch S2, a resistor R1, a resistor R2 and a capacitor C1; the weak voltage detection circuit (320) comprises a single-pole double-throw switch S3, a resistor R3, a capacitor C2, a resistor R4, a resistor R5, a resistor R6, a JFET operational amplifier AMP1, a resistor R7, a capacitor C3, a resistor R8, a resistor R9, a resistor R10, a capacitor C4 and an operational amplifier AMP2; One end of the semiconductor sample is connected to one end of the switch S1, the other end of the switch S1 is connected to one end of the switch S2, the other end of the switch S2 is connected to the other end of the semiconductor sample, and the resistor R1 is connected in parallel with the switch S2; the other end of the switch S1 is also connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C1, the other end of the capacitor C1 is grounded, and is also connected to the other end of S2; The other end of the resistor R2 is connected to the a input terminal of the single-pole double-throw switch S3; one end of the semiconductor sample is connected to one end of the resistor R3, and the other end of the resistor R3 is connected to the b input terminal of the single-pole double-throw switch S3; the other end of the resistor R3 is grounded through the capacitor C2; one end of the single-pole double-throw switch S3 is set corresponding to the a input terminal and the b input terminal, and the other end is connected to the non-inverting input terminal of the JFET operational amplifier AMP1 through the resistor R6, and the inverting input terminal of the JFET operational amplifier AMP1 is grounded through the resistor R4; the inverting input terminal of the JFET operational amplifier AMP1 is connected to the output terminal through the resistor R5; the output terminal of the JFET operational amplifier AMP1 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded through the capacitor C3; the other end of the resistor R7 is connected to the inverting input terminal of the operational amplifier AMP2 through the resistor R8, and the non-inverting input terminal of the operational amplifier AMP2 is grounded through the resistor R9; The other end of the resistor R7 is connected to the output end of the operational amplifier AMP2 via the resistor R10, and the inverting input end of the operational amplifier AMP2 is connected to the output end; When switch S1 is closed and switch S2 is open, the single-pole double-throw switch S3 is connected to input terminal a; when switch S1 is open and switch S2 is closed, the single-pole double-throw switch S3 is connected to input terminal b; The output terminal of the operational amplifier AMP2 outputs analog signals of the short-circuit current and open-circuit voltage of the semiconductor sample.

2. The photoelectric effect measurement system according to claim 1, characterized in that: The servo control module includes an encoder readout module, a PID controller and an adder. The encoder readout module is used to read the actual rotation angle in the form of a digital signal output by the absolute position encoder (232); The adder receives the rotation angle target value transmitted by the single-chip control module and subtracts the actual rotation angle in the form of a digital signal to obtain an angle increment value, which is then calculated by the PID controller to obtain a drive control signal to the motor drive module.

3. The photoelectric effect measurement system according to claim 1, characterized in that: The parallel light emitted by the collimating lens (120) is incident on the prism (210) after being selected by the rectangular hollowing out on the light shielding plate.

4. The photoelectric effect measurement system according to claim 1, characterized in that: The semiconductor sample is arranged in a dark room, and a rectangular slit is arranged in the dark room so that part of the single wavelength light beam is incident on the semiconductor sample.

5. The photoelectric effect measurement system according to claim 1, characterized in that: The weak voltage and current detection module also includes an analog-to-digital conversion circuit (330) for converting analog signals of short-circuit current and open-circuit voltage outputted from the output end of AMP2 into digital signals and inputting the digital signals into the single-chip control module.

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