Monolithic integrated micrometer-scale light emitting diode chip and applications thereof

Abstract

The application provides a monolithic integrated micron LED chip, comprising a substrate and a plurality of micron LED devices, the micron LED device comprising an n-gallium nitride layer, an indium gallium nitride / gallium nitride multiple quantum well structure, a p-aluminum gallium nitride layer, a p-gallium nitride layer, a current diffusion layer and a passivation layer, the quantum barrier thickness is 0.5-5 nm, the monolithic integrated micron LED chip can be used for light detection through a high-voltage bias circuit, the high-voltage bias circuit provides a reverse bias voltage of 0-200 V and a bandwidth of 10 MHz-10 GHz; the monolithic integrated micron LED chip can be used for light emission and has a bandwidth of 10 MHz-10 GHz. The monolithic integrated micron LED chip has good photoelectric response characteristics and bandwidth characteristics under an extremely high reverse bias voltage. The application also provides an application of the monolithic integrated micron LED chip as a narrowband photoelectric detector and an application in high-speed visible light communication, and a visible light communication device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photonic chips, in particular to a monolithic integrated micro-LED chip, application of the monolithic integrated micro-LED chip as a narrowband photodetector, a visible light communication device and application of the monolithic integrated micro-LED chip in high-speed visible light communication. BACKGROUND

[0002] With the exponential growth of Internet of Things devices and applications, traditional radio frequency (RF) communication is facing the problem of increasingly tight spectrum resources, and will not be able to meet the demand for large-scale access and high-speed wireless data rates. Visible light communication technology is a new type of wireless optical communication technology, which can combine lighting and communication, and has extremely broad application prospects and development space. Compared with traditional radio frequency, visible light communication has the advantages of unlimited spectrum, high transmission rate, large communication capacity, safety and energy saving, and is an effective supplement to radio frequency technology. The visible light communication system mainly uses LED (Light Emitting Diode) as a signal transmitter, but the bandwidth of commercial LED is only tens of MHz, which greatly limits the rate of visible light communication. In order to overcome this problem, researchers have proposed micro-LEDs (Micro-LEDs), which have the advantages of large current density, high brightness, small junction capacitance, and a modulation bandwidth of several hundred MHz, greatly improving the communication rate. In addition, the receiving end of the current visible light communication system mostly uses commercial silicon-based photodetectors, but the spectral response range of the silicon-based photodetector is wide, which will introduce optical noise. Micro-LEDs not only can be used as optical transmitting devices in visible light communication systems, but also can realize photoelectric conversion without changing the structure and material of the quantum well (MQW), and can be used as photodetectors. Micro-LED chip photodetectors have the advantages of wavelength selectivity, low dark current and high responsiveness, and at the same time, Micro-LEDs have the characteristics of self-power supply, and still produce photocurrent without external power supply.

[0003] However, the existing technology uses Micro-LED chips with single performance in visible light communication devices, which has high power consumption and cost, low modulation bandwidth, and can only reach tens to hundreds of MHz, limiting the data rate of the visible light communication device. In addition, the commercial silicon-based photodetector used in the prior art as the receiving end of the visible light communication system generates high optical noise, thereby limiting the data rate of the visible light communication device. Moreover, there is no related report on the multifunctional application of monolithic Micro-LED chips in visible light communication in the prior art.

[0004] Therefore, it is of great significance to provide a monolithic integrated Micro-LED chip, a visible light communication device adopting the monolithic integrated Micro-LED chip, and applications of the monolithic integrated Micro-LED chip in high-speed visible light communication and as a narrow-band photodetector to solve or at least alleviate the at least one technical problem. SUMMARY

[0005] In view of the above technical problems, the present application provides a monolithic integrated Micro-LED chip, a visible light communication device, applications of the monolithic integrated Micro-LED chip as a narrow-band photodetector and in high-speed visible light communication to solve or at least alleviate the at least one technical problem existing in the Micro-LED chip and the visible light communication device.

[0006] In a first aspect, the present application provides a monolithic integrated Micro-LED chip, comprising: a substrate and a plurality of Micro-LED devices arranged in an array on the substrate, each Micro-LED device comprising an n-GaN layer, an InGaN / GaN multi-quantum well structure, a p-AlGaN layer, a p-GaN layer and a current diffusion layer arranged in sequence, and a passivation layer located on the side of the InGaN / GaN multi-quantum well structure, the p-AlGaN layer, the p-GaN layer and the current diffusion layer, the quantum barrier thickness in the InGaN / GaN multi-quantum well structure being 0.5-5 nm, the monolithic integrated Micro-LED chip being capable of being used for light detection by a high-voltage bias circuit, the high-voltage bias circuit being capable of providing a reverse bias voltage of 0-200 V and a detection bandwidth of 10 MHz-10 GHz at different voltages; the monolithic integrated Micro-LED chip is also capable of being used for light emission, and the bandwidth for light emission being 10 MHz-10 GHz.

[0007] Optionally, the number of quantum well pairs in the InGaN / GaN multi-quantum well structure is 1-20.

[0008] Optionally, a first electrode layer is arranged on the surface of the current diffusion layer to form a p-contact layer; a second electrode layer is arranged on the surface of the n-GaN layer to form an n-contact layer, and the second electrode layer is arranged apart from the passivation layer.

[0009] Optionally, the first electrode layer is a Ti-Al-Ti-Au metal layer and / or the second electrode layer is a Ti-Al-Ti-Au metal layer.

[0010] Optionally, the size of each Micro-LED device is 1-100 microns.

[0011] In a second aspect, the present application provides an application of the monolithic integrated micron-scale LED chip as described in any of the preceding aspects as a narrowband photodetector, the narrowband photodetector exhibiting wavelength selectivity with a full width at half maximum spectral responsivity of 10-50 nm.

[0012] In a third aspect, the present application provides a visible light communication device, the transmitting end, the relay end, or the receiving end of the visible light communication device employing the monolithic integrated micron-scale LED chip as described in any of the preceding aspects.

[0013] Optionally, a single micron-scale LED device is employed as the transmitting end of the visible light communication device, the single micron-scale LED device employed having a -3dB modulation bandwidth of 10MHz-10GHz.

[0014] Optionally, a single micron-scale LED device is employed as the transmitting end of the visible light communication device, the visible light communication device having a communication rate of 1-100Gbps.

[0015] Optionally, a single micron-scale LED device is employed as the receiving end of the visible light communication device, the single micron-scale LED device employed having a -3dB modulation bandwidth of 10MHz-10GHz.

[0016] Optionally, a single micron-scale LED device is employed as the receiving end of the visible light communication device, the visible light communication device having a communication rate of 1-100Gbps.

[0017] In a fourth aspect, the present application provides an application of the monolithic integrated micron-scale LED chip as described in any of the preceding aspects in high-speed visible light communication, the monolithic integrated micron-scale LED chip having a bandwidth of greater than or equal to 100MHz, the high-speed visible light communication having a communication rate of greater than or equal to 10Gbps.

[0018] The beneficial effects of the present application: Different from the prior art, the monolithic integrated micron-scale light-emitting diode chip provided by the present application can bear the functions of optical signal emission, reception, modulation and processing, and also has a relatively thin quantum barrier thickness and a relatively small number of quantum well pairs, which can reduce the transit time of photo-generated carriers, and thus can exhibit excellent photoelectric response characteristics and bandwidth under extremely high reverse bias. The monolithic integrated micron-scale light-emitting diode chip of the present application provides a high reverse bias through a high-voltage bias circuit, which not only makes the device absorption region almost depleted, reduces the carrier diffusion time, but also improves the drift speed of the carrier, reduces the transit time, and further improves the bandwidth. When the monolithic integrated micron-scale light-emitting diode chip of the present application is used as a narrow-band photodetector, it exhibits wavelength selectivity at 368-416 nm, enabling narrow-band spectral response with a full width at half maximum (FWHM) of only 48 nm. The Micro-LED narrow-band photodetector can be widely used in color imaging, target recognition and other fields. Moreover, the monolithic integrated micron-scale light-emitting diode chip of the present application can not only be used as a transmitting end and a receiving end in a visible light communication system to realize Gbps high-speed communication, but also can be used as a relay end in a visible light communication system to expand the visible light communication range, reduce the link interruption probability, and improve the reliability and security of the visible light communication system. In addition, the size and overall power consumption of the photonic integrated system are also effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings.

[0020] Figure 1 The structure diagram of the monolithic integrated Micro-LED chip of the present application embodiment;

[0021] Figure 2 The structure diagram of the Micro-LED device of the present application embodiment;

[0022] Figure 3 The bandwidth characteristics of the monolithic integrated Micro-LED chip of the present application embodiment as a photodetector;

[0023] Figure 4 The current and voltage characteristic diagram of the monolithic integrated Micro-LED chip of the present application embodiment as a photodetector;

[0024] Figure 5A structure diagram of a visible light communication device when the monolithic integrated Micro-LED chip is used as a transmitting end of the visible light communication device;

[0025] Figure 6 A structure diagram of a visible light communication device when the monolithic integrated Micro-LED chip is used as a receiving end of the visible light communication device;

[0026] Figure 7 A structure diagram of a visible light communication device when the monolithic integrated Micro-LED chip is used as a relay end of the visible light communication device. Figure 6

[0027] Figure 8 A structure diagram of a visible light communication device when the monolithic integrated Micro-LED chip is used as a relay end of the visible light communication device.

[0028] The specific embodiments are as follows:

[0029] A monolithic integrated Micro-LED chip 100;

[0030] A substrate 11 and a micron-level light-emitting diode device 12;

[0031] A visible light communication device 200, 300, 400. Specific embodiments

[0032] The technical solutions of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0033] The following examples are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0035] ​In the description of the application, the terms "comprising" and "having" and any variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or device that comprises a list of steps or units is not limited to the listed steps or units, but can optionally further include steps or units not listed, or can optionally further include other steps or units inherent to such processes, methods, products or devices.

[0036] In the description of the embodiments of the application, the technical terms "side", "one side" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the application and simplifying the description, and does not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the application.

[0037] In the description of the embodiments of the application, the technical terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0038] In the present application, the term "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the application. The appearance of this phrase at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the described embodiments of the application can be combined with other embodiments.

[0039] In the description of the embodiments of the application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0040] Please refer to Figure 1 and 2The first embodiment of the present application provides a monolithic integrated micro-LED chip 100, which comprises a substrate 11 and a plurality of micro-LED devices 12 arranged in an array on the substrate 11. Each micro-LED device 12 comprises an n-GaN layer, an InGaN / GaN multi-quantum well structure, a p-AlGaN layer, a p-GaN layer, a current diffusion layer, and a passivation layer. The n-GaN layer, the InGaN / GaN multi-quantum well structure, the p-AlGaN layer, the p-GaN layer, and the current diffusion layer are stacked in a direction away from the substrate 11 on one side of the substrate 11, and the passivation layer is arranged on the side of the InGaN / GaN multi-quantum well structure, the p-AlGaN layer, the p-GaN layer, and the current diffusion layer.

[0041] The substrate 11 can be selected from, but not limited to, a sapphire substrate, a silicon substrate, a GaN substrate, a silicon carbide substrate, or a flexible PET substrate, and can also be selected from other lattice-matched substrates. In this embodiment, the substrate 11 is a sapphire substrate.

[0042] The shape of the plurality of micro-LED devices 12 can be selected according to actual needs, and can be, but is not limited to, circular, square, polygonal, etc. In this embodiment, the plurality of micro-LED devices 12 are circular.

[0043] The size of the plurality of micro-LED devices 12 can be selected according to actual needs, and can be equal or unequal. Reducing the size of the micro-LED device 12 can reduce the junction capacitance and resistance of the device, thereby reducing the RC time constant and improving the bandwidth; but too small a detector size will reduce the light coupling efficiency. Preferably, the size of each micro-LED device 12 is 1-100 μm. More preferably, the size of each micro-LED device 12 is 8-20 microns. In this embodiment, the size of the micro-LED device 12 is 20 microns. The size of the micro-LED device 12 is in microns, so that the same size monolithic integrated micro-LED chip 100 has more micro-LED devices 12, improving the efficiency of the monolithic integrated micro-LED chip 100, reducing the size of the monolithic integrated micro-LED chip 100, and more conducive to meeting the requirements of small size and low power consumption of Internet of Things technologies such as visible light communication.

[0044] The InGaN / GaN multi-quantum well structure includes a plurality of InGaN / GaN quantum wells superimposed on each other. The high-efficiency radiative recombination in the InGaN / GaN multi-quantum well structure enables the single-chip integrated Micro-LED chip to output optical signals, thereby improving the light-emitting performance of the single-chip integrated Micro-LED chip. Moreover, the InGaN / GaN multi-quantum well structure can improve the electro-optical conversion efficiency and flexibly control the response to incident light of different wavelengths by adjusting the layer structure of the multi-quantum well structure. Preferably, the number of InGaN / GaN quantum wells in the InGaN / GaN multi-quantum well structure is 1-20. The InGaN / GaN multi-quantum well structure has a small number of quantum well pairs, which can reduce the transit time of photo-generated carriers and improve the bandwidth.

[0045] The quantum barrier thickness in the InGaN / GaN multi-quantum well structure is 0.5-5 nm. The ultra-thin quantum barrier thickness can reduce the transit time and lifetime of carriers, which is conducive to improving the bandwidth of the device. In this embodiment, the quantum barrier thickness in the InGaN / GaN multi-quantum well structure is 5 nm.

[0046] Since the tunneling and hot electron emission lifetime are reduced with the decrease of the barrier height, the Micro-LED device 12 with a thinner barrier and a larger reverse bias has a shorter escape lifetime, thereby having a higher bandwidth. The Micro-LED device 12 reduces the quantum barrier thickness in the InGaN / GaN multi-quantum well structure to reduce the escape lifetime of the carriers, which is conducive to improving the bandwidth of the Micro-LED detector when the single-chip integrated Micro-LED chip 100 is used for optical detection.

[0047] The material of the current diffusion layer can be a conventional material of the current diffusion layer, which is selected according to actual needs. In this embodiment, the current diffusion layer is an indium tin oxide (ITO) layer.

[0048] Preferably, a first electrode layer is deposited on the surface of the current diffusion layer to form a p-contact layer; and a second electrode layer is deposited on the surface of the n-GaN layer to form an n-contact layer. The second electrode layer is spaced apart from the passivation layer. The first electrode layer and the second electrode layer are preferably metal electrode layers. More preferably, the material of the first electrode layer and the second electrode layer includes but is not limited to copper (Cu), aluminum (Al), titanium (Ti), gold (Au), etc. In this embodiment, a Ti-Al-Ti-Au metal layer is deposited on the surface of the ITO layer as the first electrode layer; and a Ti-Al-Ti-Au metal layer is deposited on the surface of the n-GaN layer as the second electrode layer.

[0049] The monolithic integrated Micro-LED chip 100 provides a reverse high bias voltage through the high-voltage bias circuit, not only makes the device absorption zone almost depleted, reduces the carrier diffusion time, but also improves the drift speed of the carrier, reduces the transit time, and further improves the bandwidth. The monolithic integrated Micro-LED chip 100 can be used for light detection through the high-voltage bias circuit, and the high-voltage bias circuit can provide a reverse bias voltage of 0V-200V, and the detection bandwidth is 10MHz-10GHz under different voltages; the monolithic integrated Micro-LED chip 100 can also be used for light emission, and the bandwidth for light emission is 10MHz-10GHz.

[0050] Referring to Figure 3 , the bandwidth characteristics of the monolithic integrated Micro-LED chip 100 when used for light detection. The bandwidth characteristics of a 20μm Micro-LED device 12 under different bias voltages were tested using a vector network analyzer (VNA, PicoVNA 106). The results are shown in Figure 3 It can be seen that as the bias voltage increases, the bandwidth of the Micro-LED photodetector increases, the Micro-LED photodetector can withstand an extremely high bias voltage of -70V, and exhibits ultra-high bandwidth characteristics under an extremely high bias voltage, and the highest bandwidth can reach 2.7GHz under a bias voltage of -70V.

[0051] Referring to Figure 4 , the current and voltage characteristics of the monolithic integrated Micro-LED chip 100 when used for light detection. The current-voltage characteristics of a 20μm Micro-LED photodetector were tested using a Keithley 2614B under no light and a power density of 26.5W / cm 2 . The results are shown in Figure 4 It can be seen that the dark current under zero bias is of the order of 10 -11 A, and the dark current under a bias voltage of -30V is of the order of 10 -8 A. Under light conditions, the photocurrent of a single 20μm Micro-LED photodetector can reach the order of 10 -4 A. It shows that the monolithic integrated Micro-LED chip 100 of the present application has high photoelectric conversion efficiency when used for light detection.

[0052] Preferably, the wafer curvature condition of the micro-concave is maintained during the growth of the InGaN / GaN multi-quantum well structure, and the tensile stress generated by the curvature can partially compensate for the compressive stress of the InGaN / GaN multi-quantum well structure, which is beneficial to reduce the quantum confinement Stark effect (QCSE) of the Micro-LED device 12. The inhibition of QCSE helps to enhance the overlap of the electron wave function and the hole wave function in the InGaN / GaN multi-quantum well structure region, which in turn is beneficial to improve the modulation bandwidth and quantum efficiency of the Micro-LED device 12.

[0053] The passivation layer can be any commonly used passivation layer in the Micro-LED chip, for example, but not limited to, silicon dioxide (SiO2), silicon nitride (SiN), etc. In this embodiment, the passivation layer is a SiO2 passivation layer.

[0054] In some embodiments, the monolithic integrated Micro-LED chip 100 is applied as a narrowband photodetector, which exhibits wavelength selectivity, and the full width at half maximum (FWHM) of the spectral responsivity can be, but is not limited to, 10-50 nm. In an optional embodiment, the monolithic integrated Micro-LED chip 100 is applied as a narrowband photodetector, which exhibits wavelength selectivity in the range of 368-416 nm, and the FWHM is 48 nm.

[0055] By introducing the InGaN / GaN multi-quantum well structure, the electro-optical conversion efficiency is improved, so that the monolithic integrated Micro-LED chip 100 can well realize the function of light detection, and the multi-quantum well structure can also flexibly control the response to different wavelengths of incident light by adjusting the layer structure, thereby increasing the sensitivity and response speed of the photodetector. Moreover, as the reverse electric field increases, the drift speed of the photo-generated carriers increases, the depletion layer widens, the absorption region is almost depleted, the diffusion time of the carriers is cancelled, and the junction capacitance of the device is reduced, thereby increasing the modulation bandwidth of the photodetector, and the photodetector has excellent photoelectric response characteristics under very high reverse bias. Avoid the technical problems that the electron excitation transition of the ordinary p-n junction photodetector in the prior art only occurs near the p-n junction, the electro-optical conversion efficiency is very low, and the response speed is relatively slow.

[0056] In some embodiments, the monolithic integrated Micro-LED chip 100 is applied in high-speed visible light communication, and the bandwidth of the monolithic integrated micron-scale light-emitting diode chip is greater than or equal to 100 MHz, and the communication rate of the high-speed visible light communication is greater than or equal to 10 Gbps. In some optional embodiments, the monolithic integrated Micro-LED chip 100 is applied in high-speed visible light communication, and the bandwidth of the monolithic integrated micron-scale light-emitting diode chip is greater than or equal to 100 MHz and less than or equal to 10 GHz, and the communication rate of the high-speed visible light communication is greater than or equal to 10 Gbps and less than or equal to 100 Gbps.

[0057] Referring to Figure 5 The second embodiment of the present application provides a visible light communication device 200, the transmitting end of the visible light communication device 200 adopts a monolithic integrated Micro-LED chip 100. The visible light communication device 200 includes a signal modulation unit, a signal generation unit, a signal mixing unit, a micro-LED light source, a lens series, a photodetector, a signal receiving unit and a signal processing unit. Among them, the micro-LED light source is a monolithic integrated Micro-LED chip 100, which includes all the technical features of the monolithic integrated Micro-LED chip 100 described in the first embodiment, which will not be described here.

[0058] The signal modulation unit can adopt but is not limited to intensity modulation (IM) and direct detection (DD) non-coherent system. The modulation method of the signal includes but is not limited to OOK modulation (on-off keying modulation technology), OFDM modulation (orthogonal frequency division multiplexing modulation technology), PAM modulation, etc.

[0059] The signal generation unit can be but is not limited to various signal waveform generators and digital-to-analog converters (DAC). The signal generation unit generates an electrical signal using a modulated digital signal, completes digital-to-analog conversion, and generates an alternating current signal that will be combined with a direct current signal to drive a single Micro-LED device on the monolithic integrated Micro-LED chip 100. Preferably, the signal generation unit sends a symbol rate (baud rate) of 0-10 Gbaud / s.

[0060] The signal mixing unit has multiple ports for mixing a single or multiple modulation signals and a direct current signal; among them, the "RF" port inputs the analog signal generated by the digital-to-analog conversion unit, the "DC" port inputs the direct current signal, and the output port is connected to the monolithic integrated Micro-LED chip 100, and outputs the driving signal combined with the above two.

[0061] The signal mixing unit can be but is not limited to a T-shaped bias-tee, and can also be other models of multi-port signal mixing devices.

[0062] The lens series includes but is not limited to a collimating lens of the transmitting end micro-LED light source and a focusing lens of the receiving end photodetector, which can be used to collimate the light beam to minimize the light spot reaching the photodetector, thereby maximizing the received optical power.

[0063] The photodetector preferably uses a high-sensitivity photodetector to receive optical signals and convert them into electrical signals. The photodetector includes but is not limited to an avalanche photodiode, a PIN photodiode, a photomultiplier tube, a Schottky photodiode, etc.

[0064] The signal receiving unit is an analog-to-digital converter (ADC) configured to receive the electrical signal obtained by the photodetector, complete analog-to-digital conversion, obtain signal waveform information, and export a received data file. The signal receiving unit can be various types of high-speed oscilloscopes, signal quality analysis instruments, and other analog-to-digital converters.

[0065] The signal processing unit includes a post-equalizer and a demodulation unit. The post-equalizer processes the received signal with distortion using an equalization algorithm to compensate for non-idealities during channel transmission so as to recover the original data. The demodulation unit recovers the input data according to the demodulation algorithm of different modulation methods after the data is processed by the equalizer, and obtains information such as the bit error rate and the signal-to-noise ratio of the signal through calculation.

[0066] The working principle of the visible light communication device 200 of the present example is as follows: in the case that the system components are completely normal, a perfect optical path is built, then the original binary data is encoded and modulated by the signal modulation unit, the modulated signal is combined with the direct current signal to drive a single Micro-LED device 12 on the single-chip integrated Micro-LED chip 100; at the receiving end, the photodetector receives the optical signal and converts it into an electrical signal, and the signal processing unit equalizes the collected data and then demodulates and decodes to realize data recovery. In addition, in the visible light communication device 200, the single-chip integrated Micro-LED chip 100 is made to work within a limited range, and in order to make the received optical signal optimal, a collimating lens and a focusing lens are used to maximize the received optical power.

[0067] It can be understood that when the single-chip integrated Micro-LED chip 100 is used as the transmitting end of the visible light communication device, the structure of the visible light communication device is not limited to the structure of the visible light communication device 200, and can be any visible light communication device in the prior art as long as the transmitting end uses the single-chip integrated Micro-LED chip 100. Other elements in the visible light communication device can use common elements in the prior art.

[0068] The single micron-scale light-emitting diode device in the single-chip integrated Micro-LED chip 100 of the present application is used as the transmitting end of the visible light communication device, the -3dB modulation bandwidth of the single micron-scale light-emitting diode device is 10MHz-10GHz, and the communication rate of the visible light communication device reaches 1-100Gbps.

[0069] Please refer to Figure 6The third embodiment of the present application provides a visible light communication device 300, and a receiving end of the visible light communication device 300 adopts a monolithic integrated Micro-LED chip 100. The visible light communication device 300 comprises a signal modulation unit, a signal generation unit, a first amplifier, a first direct current bias circuit, a laser diode, a lens, an objective lens, the monolithic integrated Micro-LED chip 100, a second direct current bias circuit, a second amplifier, a signal receiving unit and a signal receiving unit. The monolithic integrated Micro-LED chip 100 comprises all the technical features of the monolithic integrated Micro-LED chip 100 described in the first embodiment, which will not be described here.

[0070] The signal modulation unit and the signal generation unit can include but are not limited to a waveform generator, a voice signal, a video signal, etc. The working principle of the visible light communication device 300 is that the signal modulation unit and the signal generation unit are used to give a communication signal source, the communication signal source is amplified by the first amplifier, and then mixed with a direct current signal in the first direct current bias circuit; the laser diode is used as a transmitting end for transmitting visible light; a lens and an objective lens are used between the laser diode and the monolithic integrated Micro-LED chip 100 to collimate the transmitted light and focus the received light; the light is incident on the monolithic integrated Micro-LED chip 100 for light reception, and the optical signal is converted into an electrical signal; the monolithic integrated Micro-LED chip 100 is connected to the second direct current bias circuit at the back end to provide a negative bias voltage for the monolithic integrated Micro-LED chip 100; the electrical signal is sent to the signal receiving unit through the second amplifier, and the signal receiving unit can be but is not limited to an oscilloscope, a signal quality analysis instrument and other digital-to-analog converters; the signal processing unit demodulates and processes the signal received by the monolithic integrated Micro-LED chip 100.

[0071] In this embodiment, a 405nm laser diode is used as a light emitter for visible light communication; an orthogonal frequency division multiplexing (OFDM) modulation scheme is adopted, the modulated signal is mixed with a direct current signal in the first direct current bias circuit after being amplified by the first amplifier, and the modulated transmitted light is transmitted by the laser diode through a 0.3m free space distance; a single Micro-LED device 12 with a diameter of 20μm on the monolithic integrated Micro-LED chip 100 is used for light reception at the receiving end; a second direct current bias circuit is connected to the back end of the monolithic integrated Micro-LED chip 100, a Keithley 2614B current source is used to provide a negative bias voltage for the Micro-LED, and a bias voltage of-70V is used for the monolithic integrated Micro-LED chip 100; the signal receiving unit and the signal processing unit are used to detect the signal received by the monolithic integrated Micro-LED chip 100 by using an oscilloscope, recover the input data through demodulation code, and obtain information such as error rate and signal-to-noise ratio through calculation.

[0072] It can be understood that the Micro-LED devices 12 of different sizes in the monolithic integrated Micro-LED chip 100 can all be the receiving end, and are not limited to the 20 μm single Micro-LED device 12 in the embodiment, for example, single Micro-LED devices 12 of other sizes such as 8 μm, 10 μm, 12 μm, 15 μm, etc. can all be the receiving end.

[0073] The negative bias provided for the monolithic integrated Micro-LED chip 100 is also not limited to -70 V in the embodiment, and can be selected according to actual needs. For example, the receiving end of the visible light communication device adopts the monolithic integrated Micro-LED chip 100, and the negative bias provided for the monolithic integrated Micro-LED chip 100 can be -200-0 V.

[0074] The single micron-scale light-emitting diode device in the monolithic integrated Micro-LED chip 100 of the application is used as the receiving end of the visible light communication device, the -3 dB modulation bandwidth of the single micron-scale light-emitting diode device is 10 MHz-10 GHz, and the communication rate of the visible light communication device can reach 1-100 Gbps.

[0075] Referring to Figure 7 , the rate and bit error rate characteristics obtained when the 20 μm single Micro-LED device 12 is used as the receiving end of the visible light communication device are shown, the bit error rate characteristics under different transmission rates are tested, and when the bit error rate is lower than the forward error correction threshold 3.8 x 10 -3 When the single Micro-LED device 12 is used as the receiving end, the highest rate that can be obtained is 12.8 Gbps, and Gbps high-speed communication can be achieved.

[0076] It can be understood that when the monolithic integrated Micro-LED chip 100 is used as the receiving end of the visible light communication device, the structure of the visible light communication device is not limited to the structure of the visible light communication device 300, and can be any visible light communication device in the prior art as long as the receiving end adopts the monolithic integrated Micro-LED chip 100. Other elements in the visible light communication device can all use common elements in the prior art.

[0077] Please refer to Figure 8The fourth embodiment of the present application provides a visible light communication device 400, and a single-chip integrated micro-LED chip 100 is used in the relay end of the visible light communication device 400. The visible light communication device 400 comprises a signal modulation unit, a signal generation unit, a signal mixing unit, a laser diode, a lens series 1, the single-chip integrated micro-LED chip 100, a direct current bias circuit, an amplifier, a lens series 2, a photodetector, a signal receiving unit and a signal processing unit.

[0078] The signal modulation unit can be, but is not limited to, an intensity modulation (IM) and a non-coherent system of direct detection (DD), and the modulation method of the signal comprises, but is not limited to, OOK modulation, OFDM modulation, PAM modulation and the like.

[0079] The signal generation unit can be, but is not limited to, a waveform generator of various signals and a digital-to-analog converter (DAC). The signal generation unit generates an electrical signal by using a modulated digital signal, completes digital-to-analog conversion, and generates an alternating current signal which is combined with a direct current signal to drive the micro-LED device.

[0080] Preferably, the signal generation unit has a symbol rate (baud rate) of 0-10 Gbaud / s.

[0081] The signal mixing unit has multiple ports for mixing a single or multiple modulation signals and a direct current signal; wherein the “RF” port inputs an analog signal generated by the digital-to-analog conversion unit, the “DC” port inputs a direct current signal, and the output port is connected to the laser diode to output a driving signal combined with the above two.

[0082] The signal mixing unit can be, but is not limited to, a T-shaped bias-tee, and can also be other types of multi-port signal mixing devices.

[0083] The lens series 1 comprises, but is not limited to, a collimating lens of the transmitting end laser diode and a focusing lens of the receiving end single-chip integrated micro-LED chip 100, and can be used to focus the light beam to minimize the light spot reaching the single-chip integrated micro-LED chip 100, thereby maximizing the received light power.

[0084] The lens series 2 comprises, but is not limited to, a collimating lens of the single-chip integrated micro-LED chip 100 and a focusing lens of the receiving end photodetector, and can be used to collimate the light beam to minimize the light spot reaching the photodetector, thereby maximizing the received light power.

[0085] The photodetector preferably uses a high-sensitivity photodetector to receive the optical signal and convert it into an electrical signal. The photodetector comprises, but is not limited to, an avalanche photodiode, a PIN photodiode, a photomultiplier tube, a Schottky photodiode and the like.

[0086] The signal receiving unit is an analog-to-digital converter (ADC) configured to receive the electrical signal obtained by the photodetector, complete analog-to-digital conversion, obtain signal waveform information, and export a received data file. The signal receiving unit can be various types of high-speed oscilloscopes, signal quality analysis instruments, and other analog-to-digital converters.

[0087] The signal processing unit includes a post-equalizer and a demodulation unit. The post-equalizer processes the distorted received signal using an equalization algorithm to compensate for the non-idealities during channel transmission, so as to recover the original data. The demodulation unit recovers the input data according to the demodulation algorithm of different modulation methods after the data is processed by the equalizer, and obtains information such as the bit error rate and the signal-to-noise ratio of the signal through calculation.

[0088] The working principle of the visible light communication device 400 of the embodiment is as follows: first, a laser diode is used as a transmitting end, then original binary data is encoded and modulated, the modulated signal is combined with a direct current signal to drive the laser diode; at the relay end, a single Micro-LED device 12 on a single-chip integrated Micro-LED chip is used as a photodetector to receive an optical signal and convert it into an electrical signal, and another single Micro-LED device 12 on the single-chip integrated Micro-LED chip 100 is driven after the collected signal is amplified by an amplifier and combined with a direct current signal; at the receiving end, a photodetector is used to receive an optical signal and convert it into an electrical signal, and the collected data is post-processed to realize data recovery after demodulation and decoding. In addition, in the system, in order to make the received optical signal optimal, a lens and an objective lens are used to maximize the received optical power.

[0089] It can be understood that when the single-chip integrated Micro-LED chip 100 is used as a relay end of a visible light communication device, the structure of the visible light communication device is not limited to the structure of the visible light communication device 400, and can be any visible light communication device in the prior art as long as the relay end uses the single-chip integrated Micro-LED chip 100. Other elements in the visible light communication device can use common elements in the prior art.

[0090] The monolithic integrated Micro-LED chip provided by the application can not only bear the functions of optical signal emission, reception, modulation and processing, but also can exhibit excellent photoelectric response characteristics and modulation bandwidth under extremely high reverse bias. The monolithic integrated Micro-LED chip provided by the application can be used for optical detection through a high-voltage bias circuit, the high-voltage bias circuit can provide a reverse bias voltage of 0V-200V, and the detection bandwidth is 10MHz-10GHz under different voltages; the monolithic integrated micron-scale light-emitting diode chip can also be used for optical emission, and the bandwidth is 10MHz-10GHz when used for optical emission. The quantum potential barrier thickness in the monolithic integrated Micro-LED chip of the application is 0.5-5nm, and the ultra-thin quantum potential barrier thickness can reduce the transit time life of carriers, which is beneficial to improve the bandwidth of the device. When the monolithic integrated Micro-LED chip of the application is used as a narrow-band photodetector, the narrow-band photodetector exhibits wavelength selectivity and can realize narrow-band spectral response, and the spectral response half peak full width (FWHM) is only 10-50nm. The Micro-LED narrow-band photodetector can be widely used in the fields of color imaging and target recognition. Moreover, when the monolithic integrated Micro-LED chip is applied in high-speed visible light communication, the bandwidth of the monolithic integrated micron-scale light-emitting diode chip is greater than 100MHz, and the communication rate of the high-speed visible light communication is greater than or equal to 10Gbps. The monolithic integrated Micro-LED chip of the application can not only be used as the transmitting end and receiving end in the visible light communication system to realize high-speed communication of up to 100Gbps, but also can be used as the relay end in the visible light communication system to expand the coverage range of the visible light communication, reduce the link interruption probability, and improve the reliability and security of the visible light communication system. In addition, the size of each Micro-LED device is micron-scale, which effectively reduces the size and overall power consumption of the photonic integrated system.

[0091] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application, and they should be covered in the scope of the claims and the description of the application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A monolithically integrated micrometer-scale light emitting diode chip, characterized by, The application relates to a single-chip integrated micron-scale light-emitting diode chip, which comprises a substrate and a plurality of micron-scale light-emitting diode devices arranged in an array on the substrate, each micron-scale light-emitting diode device comprising an n-GaN layer, an InGaN / GaN multi-quantum well structure, a p-AlGaN layer, a p-GaN layer and a current diffusion layer arranged in sequence, and a passivation layer located on the side of the InGaN / GaN multi-quantum well structure, the p-AlGaN layer, the p-GaN layer and the current diffusion layer, the quantum barrier thickness of the InGaN / GaN multi-quantum well structure is 0.5-5 nm, the single-chip integrated micron-scale light-emitting diode chip can be used for light detection through a high-voltage bias circuit, the high-voltage bias circuit can provide a reverse bias voltage of 0V-200V, and the detection bandwidth under different voltages is 10MHz-10GHz; the single-chip integrated micron-scale light-emitting diode chip can also be used for light emission, and the bandwidth for light emission is 10MHz-10GHz. The number of quantum well pairs in the InGaN / GaN multi-quantum well structure is 1-20. A first electrode layer is arranged on the surface of the current diffusion layer to form a p-contact layer; a second electrode layer is arranged on the surface of the n-GaN layer to form an n-contact layer, and the second electrode layer is arranged apart from the passivation layer.

2. The monolithically integrated micrometer-scale light emitting diode chip of claim 1, wherein, The first electrode layer is a Ti-Al-Ti-Au metal layer and / or the second electrode layer is a Ti-Al-Ti-Au metal layer.

3. The monolithically integrated micrometer-scale light emitting diode chip of claim 2, wherein, The size of each micron-scale light-emitting diode device is 1-100 microns.

4. The monolithic integrated micrometer-scale light emitting diode chip of any of claims 1-3, wherein, The narrow-band photoelectric detector shows wavelength selectivity, and the full width at half maximum of spectral responsivity is 10-50 nm.

5. Use of a monolithic integrated micrometer-scale light emitting diode chip according to any one of claims 1 to 4 as a narrowband photodetector, characterized in that, The transmitting end, the relay end or the receiving end of the visible light communication device adopts the single-chip integrated micron-scale light-emitting diode chip according to any one of claims 1-4.

6. A visible light communication apparatus characterized by comprising: A single micron-scale light-emitting diode device is used as the transmitting end of the visible light communication device, and the -3dB modulation bandwidth of the single micron-scale light-emitting diode device is 10MHz-10GHz.

7. The visible light communication apparatus according to claim 6, wherein A single micron-scale light-emitting diode device is used as the transmitting end of the visible light communication device, and the communication rate of the visible light communication device reaches 1-100Gbps.

8. The visible light communication apparatus according to claim 6 or 7, wherein A single micron-scale light-emitting diode device is used as the receiving end of the visible light communication device, and the -3dB modulation bandwidth of the single micron-scale light-emitting diode device is 10MHz-10GHz.

9. The visible light communication apparatus according to claim 6, wherein A single micron-scale light-emitting diode device is used as the receiving end of the visible light communication device, and the communication rate of the visible light communication device reaches 1-100Gbps.

10. The visible light communication apparatus according to claim 6 or 9, wherein The bandwidth of the single-chip integrated micron-scale light-emitting diode chip is greater than or equal to 100MHz, and the communication rate of the high-speed visible light communication is greater than or equal to 10Gbps.

11. Use of the visible light communication device according to claim 6 in high speed visible light communication, characterized in that ​

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