Photoelectric device with light emitting and detecting functions

Abstract

The invention relates to a photoelectric device with light-emitting and detection functions, and the device comprises a light-transmitting substrate which comprises an upper surface; the buffer layer is formed on the upper surface of the light-transmitting substrate; the gallium nitride-based epitaxial layer is formed on the surface of the buffer layer, the cross section of the gallium nitride-based epitaxial layer is shaped like a Chinese character'tu ', the photoelectric device is provided with a deep channel, and the deep channel is formed from the top of the photoelectric device to the buffer layer to enable the buffer layer to be exposed out of the light-transmitting substrate; and the electrode structure is formed on the surface of the gallium nitride-based epitaxial layer. The substrate and the first electrode arranged on the top of the gallium nitride-based epitaxial layer are made of light-transmitting materials, so that the photoelectric device has the dual functions of light emitting or detection or light emitting and detection.

Description

Technical Field

[0001] This application relates to the field of semiconductor chips, and particularly to an optoelectronic device with both light-emitting and detecting functions. Background Art

[0002] Optoelectronic devices can be used as detectors, or as light-emitting devices, or require the simultaneous application of light-emitting and detecting functions. The light-emitting and detecting of optoelectronic devices have broad application prospects in fields such as biomedicine, intelligent display and interaction, and environmental monitoring.

[0003] For example, when used as a heart rate sensor in the biomedical field, it is necessary to emit green light to irradiate the skin. Part of the light is absorbed and part is reflected back. The photodetector receives the reflected light and detects the change in light intensity. These changes can reflect the information of the heart beat after being amplified and processed by the circuit; in the environmental monitoring field, a light-emitting device emits light with a specific wavelength to irradiate the substance to be measured, and the photodetector receives the reflected or transmitted light and analyzes its spectral characteristics to achieve the detection of harmful substances; in the field of intelligent display and interaction technology, the display screen integrates light-emitting diodes (LEDs) and photodetectors, which can not only display images but also detect the gestures or touch operations of users. However, in the prior art, optoelectronic devices either only achieve the function of light emission or only achieve the function of detection. There is currently no dual-functional device with both detection and light emission. This limitation not only restricts the application scope of optoelectronic devices but also hinders the further development of related technical fields. Developing an optoelectronic device that can simultaneously achieve light-emitting and detecting functions will help improve the integration of devices, reduce system complexity, and provide more possibilities for new applications.

[0004] In view of the above problems, the prior art urgently needs to be improved. Summary of the Invention

[0005] An optoelectronic device with both light-emitting and detecting functions provided by this application adopts the following technical solution: An optoelectronic device with both light-emitting and detecting functions includes: a transparent substrate including an upper surface; a buffer layer formed on the upper surface of the transparent substrate; a gallium nitride-based epitaxial layer formed on the surface of the buffer layer, the cross-section of the gallium nitride-based epitaxial layer being convex-shaped, a deep trench being provided in the optoelectronic device, the deep trench being opened from the top of the optoelectronic device until the buffer layer to expose the transparent substrate; and an electrode structure formed on the surface of the gallium nitride-based epitaxial layer, the electrode structure including a light-transmitting region that can transmit the target detection light.

[0006] By adopting the above technical solution, the optoelectronic device realizes the integration of light-emitting and detecting functions by sequentially arranging a buffer layer, a gallium nitride-based epitaxial layer, and an electrode structure on the transparent substrate.

[0007] Specifically, the first electrode is made of a light-transmitting material and can switch between the functions of light emission and detection according to different voltages connected to the second electrode or the third electrode, thereby improving the functional diversity and space utilization rate of the device. In addition, the convex-shaped cross-section design of the gallium nitride-based epitaxial layer provides an optimized spatial structure for electrode layout, which helps to improve the overall performance of the device.

[0008] In one embodiment, the electrode structure includes a first electrode formed on the top of the gallium nitride-based epitaxial layer and two independent second electrodes and third electrodes formed in the lower part of the gallium nitride-based epitaxial layer. The first electrode can alternatively connect to different voltages of the second electrode or the third electrode for light emission and / or detection; or the first electrode and the second electrode are connected with a forward bias voltage for light emission, and the first electrode and the third electrode are connected with a reverse bias voltage for detection; When the first electrode and the second electrode are connected to a first voltage V1, the optoelectronic device with both light-emitting and detecting functions is used for light emission. When the first electrode and the third electrode are connected to a second voltage V2, the optoelectronic device with both light-emitting and detecting functions is used for detection. When the first electrode and the second electrode / or the third electrode are connected to a third voltage V3, the optoelectronic device with both light-emitting and detecting functions is used for detection and light emission, and V2 < V3 < V1.

[0009] By adopting the above technical solution, the optoelectronic device can switch between the functions of light emission and / or detection according to different connected voltages. Specifically, when the first electrode and the second electrode are connected to the first voltage V1, the optoelectronic device tends to emit light efficiently, which benefits from the design of the voltage range of V1 that improves the carrier recombination efficiency in the gallium nitride-based epitaxial layer; when the first electrode and the third electrode are connected to the second voltage V2, the optoelectronic device tends to detect sensitively, because the negative voltage or low positive voltage characteristic of V2 optimizes the carrier separation efficiency, thereby enhancing the signal detection ability; and when the first electrode and the second electrode or the first electrode and the third electrode are connected to the third voltage V3, the optoelectronic device can achieve a balance between detection and light emission, that is, it has a certain light emission intensity and detection sensitivity at the same time, because V3 is in a specific voltage range between V1 and V2, and the externally incident light signal and the self-generated light signal can be separated.

[0010] In one embodiment, the range of the first voltage V1 is 1.5V < V1 < 5V; the range of the second voltage V2 is -20V ≤ V2 < 1.0V; the range of the third voltage V3 is 1.0 ≤ V3 ≤ 1.5V.

[0011] In one embodiment, the second electrode is a mesh structure and the third electrode is a columnar structure.

[0012] By adopting the above technical solution, the second electrode of the optoelectronic device adopts a mesh structure, which can effectively reduce the light shielding, improve the light transmittance, and thus is beneficial to the transmission of the target detection light. At the same time, the third electrode adopts a columnar structure, which helps to optimize the electric field distribution and improve the sensitivity and accuracy of the detection function. In addition, the combined design of the mesh structure and the columnar structure enables the electrode to achieve efficient conductivity while further reducing the interference with the optical performance of the optoelectronic device, realizing the collaborative optimization of the light emission and detection functions.

[0013] In one embodiment, the optoelectronic device is provided with a deep trench, and the deep trench is opened from the top of the optoelectronic device until the buffer layer to expose the transparent substrate.

[0014] In one embodiment, the deep trench includes a first trench and a second trench communicating with the first trench. The gallium nitride-based epitaxial layer includes an n-type gallium nitride layer, a multi-quantum well layer, an electron blocking layer, and a p-type gallium nitride layer sequentially located on the surface of the buffer layer. The first trench penetrates through the electrode layer, the p-type gallium nitride layer, the electron blocking layer, and the multi-quantum well layer, and the second trench penetrates through the n-type gallium nitride layer and the buffer layer. The width of the first trench is greater than the width of the second trench.

[0015] In one embodiment, the multi-quantum well layer, the electron blocking layer, and the p-type gallium nitride layer are aligned. The multi-quantum well layer exposes a part of the n-type gallium nitride layer. The first electrode is formed on the surface of the part of the n-type gallium nitride layer exposed by the multi-quantum well layer, and the second electrode is formed on the surface of the p-type gallium nitride layer. A transparent protective layer is provided on the side wall of the gallium nitride-based epitaxial layer and the surface of the electrode layer.

[0016] In one embodiment, the first electrode includes an indium tin oxide layer formed on the surface of the p-type gallium nitride layer and a metal layer formed on the surface of the indium tin oxide layer. The metal layer exposes a part of the indium tin oxide layer.

[0017] In one embodiment, the top surface of the optoelectronic device with both light emission and detection functions is a first circle with a diameter of D, and the first electrode is a second circle with a diameter of d1. The second circle is concentric with the first circle, and the area between the first circle and the second circle is the sensing area.

[0018] In one embodiment, the sensing area is divided into a plurality of sensing sub-areas, and adjacent sensing sub-areas are separated by a metal layer.

[0019] By adopting the above technical solution, the sensing area of the optoelectronic device is divided into multiple sensing sub-areas, and adjacent sensing sub-areas are separated by a metal layer. This design can improve the spatial resolution of the sensing area, enabling the optoelectronic device to more accurately locate and distinguish different light sources or signal sources in the detection mode. At the same time, the spacer structure of the metal layer helps to reduce the interference between the sensing sub-areas, improving the sensitivity and accuracy of detection.

[0020] In one embodiment, a reflective layer is provided on the side of the transparent substrate facing away from the buffer layer. The reflective layer is a third circle with a diameter of d2, which is concentric with the second circle, and d2 ≤ d1.

[0021] By adopting the above technical solution, the setting of the reflective layer can effectively improve the optical performance of the optoelectronic device. Specifically, the reflective layer is concentric with the first electrode and has a diameter less than or equal to that of the first electrode, which can reflect the downward light back upward when the optoelectronic device emits light, thereby improving the light emission efficiency. In addition, this design can also reduce the scattering and absorption of light on the back surface of the transparent substrate, further enhancing the light emission intensity and detection sensitivity of the optoelectronic device.

[0022] In one embodiment, a groove is formed on the side of the transparent substrate facing away from the buffer layer. The reflective layer includes a first nano-microsphere layer with a smaller particle size and a second nano-microsphere layer with a larger particle size.

[0023] By adopting the above technical solution, the setting of the groove can effectively increase the surface area of the side of the transparent substrate facing away from the buffer layer, thereby improving the bonding force between the reflective layer and the transparent substrate. The combined design of the first nano-microsphere layer and the second nano-microsphere layer endows the reflective layer with excellent reflection performance. The first nano-microsphere layer with a smaller particle size can fill the voids between the particles to form a flatter surface, reducing the scattering loss of light, while the second nano-microsphere layer with a larger particle size can further enhance the reflection effect, improving the efficiency of the optoelectronic device in the light emission mode and the sensitivity in the detection mode.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. By making the substrate a transparent material, the top of the optoelectronic device includes a transparent area that can transmit the target detection light. Thus, the external target detection light is absorbed in the epitaxial layer to generate photo-generated carriers. The photo-generated carriers form a photocurrent under the action of the electrode structure. The photocurrent is the electrical output signal of the device and is used as a detection signal. The strength of the detection signal directly reflects the key detection performance indicators such as the detection sensitivity, response speed, and signal-to-noise ratio of the device. When a forward bias is applied between the electrode structures: electrons are injected from n-type GaN, holes are injected from p-type GaN, and the carriers recombine at the bottom of the convex-shaped structure to emit photons, thus being used as a light-emitting device. 2. By varying the voltage applied to the control electrode, the externally incident optical signal and the self-generated optical signal can be separated, enabling the optoelectronic device to perform functions such as light emission, detection, or both light emission and detection. Additionally, by shaping the second and third electrodes differently, when the first electrode is connected to the second or third electrode, it is conducive to the recombination of electrons and holes to generate photons for light emission, or it optimizes the carrier separation efficiency and enhances the detection sensitivity. 3. By forming a groove on the surface of the substrate opposite to the buffer layer and forming a reflective layer in the groove, the light extraction effect of the substrate can be improved when the optoelectronic device is used as a light-emitting device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. 9 is a schematic structural diagram of an optoelectronic device with both light-emitting and detecting functions provided by the first embodiment of the present application; Figure 2 FIG. Figure 1 FIG. 14 is a schematic plan view of an optoelectronic device with both light-emitting and detecting functions provided by...; Figure 3 FIG. Figure 1 FIG. 19 is a schematic diagram comparing the EL spectrum and absorption spectrum of an optoelectronic device with both light-emitting and detecting functions provided by...; Figure 4 FIG. Figure 1 FIG. 24 is a schematic diagram of the frequency response test results of an optoelectronic device with both light-emitting and detecting functions provided by...; Figure 5 FIG. 27 is a schematic structural diagram of an optoelectronic device with both light-emitting and detecting functions provided by the second embodiment of the present application; Figure 6 FIG. Figure 5 FIG. 32 is a schematic structural diagram of the first electrode included in an optoelectronic device with both light-emitting and detecting functions provided by...;

[0026] DESCRIPTION OF REFERENCE NUMERALS: 100, optoelectronic device with both light-emitting and detecting functions; 1, transparent substrate; 2, buffer layer; 3, gallium nitride-based epitaxial layer; 4, electrode structure; 41, first electrode; 42, second electrode; 43, third electrode; 101, deep trench; 111, first trench; 112, second trench; 30, n-type gallium nitride layer; 31, multi-quantum well layer; 32, electron blocking layer; 33, p-type gallium nitride layer; 5, transparent protective layer; 410, indium tin oxide layer; 420, metal layer; 6, reflective layer; 61, first nano-microsphere layer; 62, second nano-microsphere layer; 120, sensing region; 122, sensing sub-region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of the present invention, not all possible implementations. Those skilled in the art can completely combine the embodiments of the present invention to obtain other embodiments without creative work, and these embodiments are also within the protection scope of the present invention.

[0028] In the prior art, when optoelectronic devices achieve the switching between the functions of light emission and detection, there are generally problems such as complex structure, high cost, or limited performance. For this reason, this application mainly adopts an optoelectronic device with both light-emitting and detecting functions, including a transparent substrate 1, a buffer layer 2, a gallium nitride-based epitaxial layer 3, and an electrode structure 4.

[0029] This design enables an optoelectronic device to simultaneously undertake the functions of emitting light and receiving target detection light for detection, thereby realizing two-way communication. The following is a further detailed description of this application.

[0030] Embodiment 1 Specifically, the transparent substrate 1 serves as the basic structure of the entire optoelectronic device, and a buffer layer 2 is formed on its upper surface. The transparent substrate 1 can be made of sapphire, aluminum nitride, or other transparent materials, and has good optical transmittance and mechanical strength. In this embodiment, the transparent substrate 1 is a patterned substrate.

[0031] The main function of the buffer layer 2 is to relieve the lattice mismatch and thermal stress between the transparent substrate 1 and the gallium nitride-based epitaxial layer 3. It is usually composed of gallium nitride or similar materials, and the thickness range is 0.5 μm to 2 μm.

[0032] The cross-section of the gallium nitride-based epitaxial layer 3 is convex, and the side wall of the gallium nitride-based epitaxial layer 3 is used to form one of the electrode structures 4.

[0033] The electrode structure 4 can adopt indium tin oxide (ITO) or a combination of an indium tin oxide layer and other metal layers.

[0034] For an optoelectronic device with both light-emitting and detecting functions provided by this application, the substrate is made of a light-transmitting material and can transmit the target detection light. When the optoelectronic device is irradiated by external light, photons enter the epitaxial layer. The energy of the photons is absorbed by the semiconductor material, exciting electrons to transition from the valence band to the conduction band, generating electron-hole pairs. The generated electrons and holes are separated under the action of the built-in electric field (such as the p-n junction electric field). The electrons move towards the n-type region, and the holes move towards the p-type region. The separated electrons and holes are collected by the electrodes on the surface of the epitaxial layer respectively, forming a photocurrent. By measuring the magnitude of the photocurrent, the intensity and characteristics of the incident light can be determined, realizing the detection of optical signals; Meanwhile, when an external voltage is applied to the electrodes, current is injected through the electrodes, and electrons and holes recombine in the multiple quantum well structure to generate photons. The generated photons are emitted through the light-transmitting region, and part of the light generated by the photons is reflected by the reflective layer 6 and then emitted, and finally used as a light-emitting device.

[0035] The electrode structure 4 includes a first electrode 41 formed on the top of the gallium nitride-based epitaxial layer 3 and two independent second electrodes 42 and third electrodes 43 formed on the lower part of the gallium nitride-based epitaxial layer 3. The second electrode 42 and the third electrode 43 may have the same or different structures, and the first electrode 41 can alternatively be connected to the second electrode 42 or the third electrode 43 to apply different voltages for light emission and / or detection.

[0036] Or the first electrode 41 and the second electrode 42 are connected with a forward bias voltage for light emission, and the first electrode 41 and the third electrode 43 are connected with a reverse bias voltage for detection.

[0037] Specifically, when the optoelectronic device is used as a light-emitting device or a detector, the first electrode 41 serves as a common electrode and is connected to one of the second electrode 42 or the third electrode 43 for light emission or detection or simultaneously as a detector and a light-emitting device. When used simultaneously as a detector and a light-emitting device, the first electrode 41 serves as a common electrode, and when connecting to the second electrode 42 or the third electrode 43, it is necessary to stagger the peaks of the target detection light and the self-emitted light. For example, by controlling the magnitude of the applied voltage, the visible light generated and the target detection light from the outside are minimized to avoid signal crosstalk and affect the detection accuracy. By reducing the voltage, the light intensity emitted by the device itself can be effectively reduced. When the device operates as a detector, if the self-emitted light intensity is too high, it will become the background noise of the detector, drowning or interfering with the weak target detection light signal from the outside. By precisely controlling the voltage, the self-emitted light intensity can be reduced to a low enough level to reduce the interference with the detection signal.

[0038] Specifically, when the first electrode 41 and the second electrode 42 / the third electrode 43 are connected to the first voltage V1 (1.5V <V1<5V)时,能达到光电器件的发光阈值电压,当电压超过这个阈值时,器件开始发光,电压越高,发光强度越大,但是基于光电器件的使用寿命考虑,第一电压的最大值设置为5V;当第一电极41与第二电极42 / 第三电极43接通第二电压V2(-20V≤V2<1.0V且不为零)时,通过控制第二电压V2的范围,将其减弱到不发光,体现探测器的功能;当第一电极41与第二电极42 / 第三电极43接通第三电压V3(1.0≤V3≤1.5V)时,目标探测光及自发光的峰值错开,尽量减少产生的可见光与外界的目标探测光发生信号串扰,光电器件可以同时实现发光与探测功能,通过控制第三电压V3的范围,以精确控制自发光的强度,将其减弱到不会显著干扰探测功能的水平,同时仍能维持必要的发光功能。

[0039] In the emission mode, a higher voltage can provide enough energy to drive carrier injection and recombination, thus achieving efficient luminescence. In the detection mode, a lower reverse bias voltage can effectively collect photogenerated carriers while avoiding excessive voltage that causes an increase in the device's thermal noise.

[0040] Specifically, the gallium nitride-based epitaxial layer 3 is formed by stacking an n-type gallium nitride layer 30, a multi-quantum well layer 31, an electron blocking layer 32 and a p-type gallium nitride layer 33 in sequence. The n-type gallium nitride layer 30 and the p-type gallium nitride layer 33 are doped with silicon and magnesium, respectively, to adjust the conductive properties. The multi-quantum well layer 31 is composed of alternately grown InGaN and GaN thin layers to achieve efficient light emission and light absorption. The electron blocking layer 32 is composed of AlGaN material to prevent electron overflow and improve device efficiency.

[0041] The first electrode 41 is located on the top of the gallium nitride-based epitaxial layer 3, and is in the form of a combination of an indium tin oxide (ITO) layer 410 and a metal layer 420, wherein the metal layer 420 only covers a portion of the surface of the indium tin oxide layer 410 to ensure sufficient light transmittance. The thickness of the metal layer 420 is relatively thin and can basically achieve light transmittance. In this embodiment, the thickness of the metal layer 420 is 550nm.

[0042] More specifically, in the present application, the second electrode 42 is in a mesh structure, distributed in the lower region of the gallium nitride-based epitaxial layer 3 , and is mainly used to inject current to achieve a light-emitting function.

[0043] The third electrode 43 is a columnar structure, and is composed of a metal column array.

[0044] To further optimize the device performance, the optoelectronic device is provided with a deep trench 101 that penetrates from the top of the optoelectronic device to the buffer layer 2, exposing the buffer layer 2 to the transparent substrate 1. In fact, when the optoelectronic device operates in the light-emitting mode (LED), it is necessary to maximize the efficiency of light emission from the inside of the device to the outside (high light extraction efficiency); when operating in the detection mode (PD), it is necessary to maximize the efficiency of external incident light absorption by the device (high light absorption efficiency). The deep trench changes the internal light propagation path. The deep trench helps to disperse the light emission or incident light originally confined within a certain emission angle to a wider angular range, thereby improving the light extraction efficiency during light emission and the incident light coupling efficiency during detection. Since the deep trench guides the light to interact with the active layer at different angles and paths multiple times, it may enable the device to have a better response to a spectral range (or incident angle range) within a certain width, ultimately further enhancing the light emission effect and / or the sensitivity of detection.

[0045] The deep trench 101 includes a first trench 111 and a second trench 112. The first trench 111 penetrates the electrode layer, p-type gallium nitride layer (GaN) 33, electron blocking layer 32, and multiple quantum well layer 31. The second trench 112 penetrates the n-type gallium nitride layer 30 and the buffer layer 2, and the width of the first trench 111 is greater than the width of the second trench 112. The first trench 111 penetrates the p-type layer to the multiple quantum well layer, forming a "carrier potential barrier wall" that confines the light-emitting region to the area between the trenches; the second trench 112 extends to the buffer layer to establish an "electrical isolation wall", making the detection region form an independent potential well. The double trenches cooperate to generate a three-dimensional confinement field, and the carriers are confined between the trenches (laterally) and within the quantum wells (longitudinally) during light emission.

[0046] In this embodiment, the width-depth ratio (W1 / D1) of the first trench is >1, forming a divergent electric field to promote the lateral diffusion of carriers.

[0047] The narrow-depth feature (W2 / D2) of the second trench is <1, constructing a focusing electric field to enhance the collection of photo-generated carriers.

[0048] In this embodiment, the maximum photoelectric conversion efficiency (η max ) and the parameters of the trench satisfy: where W2, W1, D2, and D1 are the width of the second trench, the width of the first trench, the depth of the second trench, and the depth of the first trench respectively, η0 represents the intrinsic efficiency without a trench, and the cosine term characterizes the phase matching between the light field distribution and the carrier transport.

[0049] In addition, a transparent protective layer 5, such as a silicon dioxide or silicon nitride thin film, is provided on the sidewalls of the gallium nitride-based epitaxial layer 3 and part of the surface of the electrode to protect the device from the external environment. In this embodiment, the transparent protective layer 5 is a SiO2 passivation layer.

[0050] The larger width of the first channel 111 can ensure that under the action of the electric field, carriers are more uniformly excited and transmitted in the multi-quantum well layer region, while avoiding the over-strong electric field concentration effect. The narrower second channel 112 helps to provide a more concentrated electric field in the n-type gallium nitride layer, ensuring the effective transmission of electrons and avoiding electron scattering and efficiency degradation caused by excessive electric fields. In this embodiment, the width of the first channel 111 is between 20 μm and 50 μm, and the width of the second channel 112 is between 5 μm and 10 μm.

[0051] Specifically, in this application, the metal organic chemical vapor deposition (MOCVD) technique is used to grow the GaN layer on the sapphire substrate.

[0052] This GaN layer serves as the base layer of the photodetector, providing stable electronic properties.

[0053] n-GaN layer: The n-type GaN layer is used for electron injection to enhance the response ability of the photodetector. The multi-quantum well structure (MQWs) between the n-GaN layer and the p-GaN layer is used to improve the light absorption efficiency of the photodetector and optimize the optoelectronic characteristics.

[0054] p-GaN layer: The p-type GaN layer serves as the hole injection layer to ensure the stable performance of the photodetector. ITO electrode: A 40-nm indium tin oxide (ITO) electrode is deposited by magnetron sputtering technology to achieve the function of a transparent electrode and maintain high light transmittance.

[0055] The implementation principle of this embodiment is as follows: By reasonably designing the structures and the coordination relationships of the light-transmitting substrate 1, the buffer layer 2, the gallium nitride-based epitaxial layer 3, and the electrode structure 4, the optimal working state of the optoelectronic device is achieved.

[0056] To avoid interference between the transmitted signal and the received signal, the present invention reduces the crosstalk phenomenon by controlling the different voltages applied and designing a large gap between the emission spectrum and the absorption spectrum. Please refer to Figure 3 , specifically, when the optoelectronic device is used as a detector, the peak emission spectrum is located near 605 nm, while the peak of the absorption spectrum is set at 385 nm. There is a large gap between the two, effectively avoiding the received light by the detector, reducing crosstalk, and improving the overall performance of the system.

[0057] We have conducted multiple performance tests on the optoelectronic device. The tests include the evaluation of the transmittance, response time, frequency response, and data transmission rate of optical signals with different wavelengths.

[0058] Please refer to Figure 4, This picture shows the normalized frequency response curves of the optoelectronic device as a detector under different bias voltages (-10V, -20V, -30V). X-axis (frequency): 10MHz to 1000MHz (1GHz), covering the high-frequency range. Y-axis (response): normalized gain (dB), 0dB represents the ideal response, and negative values represent signal attenuation.

[0059] The three curves correspond to different bias voltages respectively: -10V (green line): It has the best low-frequency response, but the most significant high-frequency attenuation.

[0060] -20V (blue line): It is in an intermediate state.

[0061] -30V (red line): Its low-frequency response is slightly weaker, but the high-frequency attenuation is relatively gentle.

[0062] All curves approach 0dB at low frequencies (<100MHz), but gradually attenuate as the frequency increases, conforming to the behavior of a low-pass filter (allowing low frequencies to pass and suppressing high frequencies). The -3dB point (where the signal attenuates to 70%): The cut-off frequency range can be inferred through the dotted line (such as the -2dB reference line).

[0063] Voltage dependence: The higher the voltage (such as -10V), the better the low-frequency gain, but the steeper the high-frequency roll-off (possibly due to device non-linear effects). The lower the voltage (such as -30V), the more gentle the high-frequency attenuation, but there is a slight sacrifice in the low-frequency response.

[0064] When the frequency > 500MHz, fluctuations occur in the curves (especially for -10V).

[0065] The experimental results show that the transparent optoelectronic detector designed by the present invention has achieved an ideal effect in terms of light transmittance, and the maximum transmission rate has reached 15.64Gbps. At the same time, the experiment has also verified that in a multi-user communication environment, the system can successfully maintain high-speed transmission and secure communication, with the maximum rate reaching 6.84Gbps.

[0066] Taking the actual test results as an example, the wavelength of the laser used in the test is 405nm, and the spot size is 170μm. When the laser is incident on the surface of the PD, its interaction can be mainly divided into five regions: Combined with Figure 1 , Region 1 represents the light irradiating on the P-type electrode metal, Region 2 represents the light irradiating on the P-type electrode metal layer 420, Region 3 represents the light passing through the silicon dioxide passivation layer and the patterned substrate, Region 4 represents the light passing through the silicon dioxide passivation layer, n-type GN, buffer layer 2 and the patterned substrate, and Region 5 represents the light passing through the entire structure.

[0067] Through experimental tests, we can specifically calculate the transmittance values of different regions of the GaN-based MQW structure PD for a 405 nm laser. Regions 1 and 2 are covered by a 550 nm thick metal layer 420, which means that light cannot penetrate in these regions, and their transmittance is 0. For Region 3, including the SO2 passivation layer and the patterned sapphire, the measured transmittance is 0.3571. For Region 4, which includes the SiO2 passivation layer, n-GaN, buffer layer 2, and the patterned sapphire, the transmittance is 0.2143. The comparison between the laser spot size and the micro PD is as Figure 3 shown. The diameter of the laser spot is approximately 170 um, and the overall transmittance is 0.072. Regions 1 and 2 account for 19.79% of the total area, Region 3 accounts for 65.40%, Region 4 accounts for 12.40%, and Region 5 accounts for 2.42%. These data indicate that there are significant differences in the laser transmission capabilities of different regions. Since Regions 1 and 2 are covered by the metal layer 420, blocking the passage of light, most of the light energy mainly enters the device through Regions 3 and 4. The higher transmittance of Region 3 indicates that it makes the greatest contribution to light transmission.

[0068] Example 2 Please refer to Figures 5 - 6 , the difference between this example and the above example is that: the top surface of the optoelectronic device with both light-emitting and detecting functions is a first circle with a diameter of D, the first electrode 41 is a second circle with a diameter of d1, the second circle is concentrically arranged with the first circle, and the area between the first circle and the second circle is the sensing area 120; the sensing area 120 is divided into multiple sensing sub-areas 122, and adjacent sensing sub-areas 122 are separated by the metal layer 420.

[0069] The design of the sensing area 120 is further optimized by dividing the sensing area 120 into multiple sensing sub-areas, and adjacent sensing sub-areas 122 are separated by the metal layer 420. This design can improve the detection sensitivity and spatial resolution and is suitable for complex optical signal processing scenarios.

[0070] When the system needs to collect optical information of different wavelengths for multispectral imaging or multi-channel signal processing, target detection lights of different wavelengths can be used to irradiate different sensing sub-areas 122 simultaneously. For example, in biological imaging, remote sensing detection, or environmental monitoring, lights of different wavelengths can be used to capture the reflection or absorption characteristics of different substances or regions. At this time, the target detection lights of each wavelength irradiate different sensing areas 120, and different signals are detected respectively; or in a spectral analysis system for medical diagnosis, by irradiating different sensing sub-areas 122 with lights of different wavelengths, multiple information such as blood oxygen content, tissue type, and lesion area can be measured simultaneously. This multi-parameter measurement requires the target detection lights of different wavelengths to work simultaneously in order to obtain more measurement results in one measurement cycle.

[0071] In addition, a reflective layer 6 is provided on the side of the light-transmitting substrate 1 facing away from the buffer layer 2. The reflective layer 6 is a third circle with a diameter of d2. The third circle is concentric with the second circle of the first electrode 41, and d2 < d1. By providing the reflective layer 6 on the side of the light-transmitting substrate 1 facing away from the buffer layer 2, photons generated by the recombination of the epitaxial layer can have a reflection angle, so that more light is emitted from the front of the optoelectronic device.

[0072] In a further embodiment, the reflective layer 6 is composed of a first nano-microsphere layer 61 with a smaller particle size and a second nano-microsphere layer 62 with a larger particle size. The particle size of the nano-microspheres included in the first nano-microsphere layer 61 is smaller than that of the nano-microspheres included in the second nano-microsphere layer 62. The nano-microspheres are used to reflect the generated signal light. More specifically, the nano-microsphere layer is formed by dispersing some nano-microspheres in a light-transmitting resin material, which is used to enhance the reflection effect of the optical signal and improve the detection efficiency.

[0073] The nano-microsphere layer with a smaller particle size can provide finer scattering and reflection, so that the photons have undergone one scattering and reflection before entering the nano-microsphere layer with a larger particle size, increasing the optical path length. The nano-microsphere layer with a larger particle size: The nano-microsphere layer with a larger particle size can provide a stronger reflection and scattering effect, further increasing the optical path length and reducing the light loss. By laminating nano-microsphere layers with different particle sizes, multiple reflections and scatterings can be achieved, significantly improving the reflection efficiency. This design can reduce the absorption and loss of light in the substrate and improve the light extraction efficiency.

[0074] The implementation principle of this embodiment is: By optimizing the layout of the sensing area 120 and introducing the design of the reflective layer 6, the detection performance of the optoelectronic device is further improved. Specifically, the division of the sensing sub-areas 122 enables the optoelectronic device to accurately detect optical signals at different positions, and the design of the reflective layer 6 enhances the reflection intensity of the optical signal, thereby improving the detection sensitivity. This design is particularly suitable for application scenarios that require high-precision optical signal processing, demonstrating excellent technical advantages.

[0075] The above are all the preferred embodiments of this application. The protection scope of this application is not limited accordingly. Therefore, any equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. An optoelectronic device with both light-emitting and detecting functions, characterized in that, Comprising: A transparent substrate (1) having an upper surface; A buffer layer (2) formed on the upper surface of the transparent substrate (1); A gallium nitride-based epitaxial layer (3) formed on the surface of the buffer layer (2), the cross-section of the gallium nitride-based epitaxial layer (3) being convex-shaped, and the optoelectronic device having a deep trench (101) that extends from the top of the optoelectronic device to the buffer layer (2) to expose the transparent substrate (1); and An electrode structure (4) formed on the surface of the gallium nitride-based epitaxial layer (3), the electrode structure (4) including a light-transmitting region that can transmit target detection light.

2. The optoelectronic device with both light-emitting and detecting functions according to claim 1, characterized in that, The electrode structure (4) includes a first electrode (41) formed on the top of the gallium nitride-based epitaxial layer (3) and two independent second electrodes (42) and third electrodes (43) formed at the lower part of the gallium nitride-based epitaxial layer (3), and the first electrode (41) can alternatively connect to the second electrode (42) or the third electrode (43) to apply different voltages for light emission and / or detection; or The first electrode (41) and the second electrode (42) are connected with a forward bias voltage for light emission, and the first electrode (41) and the third electrode (43) are connected with a reverse bias voltage for detection.

3. The optoelectronic device with both light-emitting and detecting functions according to claim 2, wherein When the first electrode (41) and the second electrode (42) are connected to a first voltage V1, the optoelectronic device with both light-emitting and detecting functions is used for light emission. When the first electrode (41) and the third electrode (43) are connected to a second voltage V2, the optoelectronic device with both light-emitting and detecting functions is used for detection. When the first electrode (41) and the second electrode (42) / or the third electrode (43) are connected to a third voltage V3, the optoelectronic device with both light-emitting and detecting functions is used for detection and light emission, and V2 < V3 < V1.

4. The optoelectronic device with both light-emitting and detecting functions according to claim 2, wherein The range of the first voltage V1 is 1.5V < V1 < 5V; the range of the second voltage V2 is -20V ≤ V2 < 1.0V and not zero; the range of the third voltage V3 is 1.0 ≤ V3 ≤ 1.5V.

5. The optoelectronic device with both light-emitting and detecting functions according to claim 2, wherein The second electrode (42) is a mesh structure, and the third electrode (43) is a columnar structure.

6. The optoelectronic device with both light-emitting and detecting functions according to claim 2, characterized in that, The deep trench (101) includes a first trench (111) and a second trench (112) communicating with the first trench (111). The gallium nitride-based epitaxial layer (3) includes an n-type gallium nitride layer (30), a multiple quantum well layer (31), an electron blocking layer (32), and a p-type gallium nitride layer (33) sequentially located on the surface of the buffer layer (2). The first trench (111) penetrates through the first electrode (41), the p-type gallium nitride layer (33), the electron blocking layer (32), and the multiple quantum well layer (31). The second trench (112) penetrates through the n-type gallium nitride layer (30) and the buffer layer (2). The width of the first trench (111) is greater than the width of the second trench (112); wherein, the width-depth ratio of the first trench (111) satisfies (W1 / D1) > 1, and the width-depth ratio of the second trench (112) satisfies (W2 / D2) < 1.

7. The optoelectronic device with both light-emitting and detecting functions according to claim 6, wherein, The maximum photoelectric conversion efficiency (η max ) of the optoelectronic device and the parameters of the deep trench (101) satisfy: wherein, W2, W1, D2, and D1 are respectively the width of the second channel (112), the width of the first channel (111), the depth of the second channel (112), and the depth of the first channel (111), η0 represents the intrinsic efficiency without a channel, and the cosine term characterizes the phase matching between the optical field distribution and the carrier transport.

8. The optoelectronic device with both light-emitting and detecting functions according to claim 7, characterized in that, A transparent protective layer (5) is provided on the sidewalls of the gallium nitride-based epitaxial layer (3) and a partial surface of the electrode structure (4); the first electrode (41) includes an indium tin oxide layer (410) formed on the surface of the p-type gallium nitride layer (33) and a metal layer (420) formed on the surface of the indium tin oxide layer (410), and a part of the indium tin oxide layer (410) is exposed by the metal layer (420).

9. The optoelectronic device with both light-emitting and detecting functions according to claim 2, wherein The top surface of the optoelectronic device having both light-emitting and detecting functions is a first circle with a diameter of D, the first electrode (41) is a second circle with a diameter of d1, the second circle is concentrically arranged with the first circle, and the area between the first circle and the second circle is a sensing area (120); the sensing area (120) is divided into a plurality of sensing sub-areas (122), and adjacent sensing sub-areas (122) are separated by the metal layer (420).

10. The optoelectronic device with both light-emitting and detecting functions according to any one of claims 1-9, characterized in that, A reflective layer (6) is provided on the side of the transparent substrate (1) facing away from the buffer layer (2), the reflective layer (6) is a third circle with a diameter of d2, the third circle is concentrically arranged with the second circle, and d2 < d1; or A groove is formed on the side of the transparent substrate (1) facing away from the buffer layer (2), the reflective layer (6) includes a first nano-microsphere layer (61) and a second nano-microsphere layer (62), and the particle size of the nano-microspheres included in the first nano-microsphere layer (61) is smaller than the particle size of the nano-microspheres included in the second nano-microsphere layer (62).

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