With the rapid development of the information age, information dissemination is closely related to human life, and optical signals are widely used as carriers for disseminating information. At the terminal of information transmission, it is necessary to convert optical signals into electrical signals for information processing and storage, and photodetectors, as components capable of photoelectric conversion, have a large number of important applications in optoelectronic systems. After the US Pelosi blatantly jumped into power, the Chinese People’s Liberation Army held an unprecedented large-scale military exercise around Taiwan in order to defend the dignity of the country and the territorial integrity of the motherland. , reminding us that the role of photoelectric detectors in the military field should not be underestimated. The guidance method of military missiles is mainly based on infrared guidance. This allows the missile to adapt to a more complex electronic countermeasure environment and accurately detect and locate the light source, thereby greatly improving the missile’s hit capability. In the medical field, with the outbreak of the new crown epidemic, non-contact body temperature detection has become a major guarantee to cut off the transmission of the virus and ensure the safety of life. Infrared photodetectors can detect the intensity of infrared light emitted by the human body, thereby correctly judging the temperature of the human body, making an indelible contribution to the prevention and control of the epidemic. At the same time, in the field of imaging, the photodetector is one of the core components of the CMOS image sensor, which can convert the corresponding visible light signal into a charge signal through the photoelectric effect, and then through the role of the amplifier circuit and the control module, this colorful and wonderful world presented before our eyes. How Photodetectors Work Photodetectors play an important role in converting light into electricity in optical communication systems, which is mainly based on the photovoltaic effect of semiconductor materials. The so-called photovoltaic effect refers to the different parts of inhomogeneous semiconductors or semiconductors combined with metals The phenomenon of potential difference between them. To understand how photodetectors work. We first need to know the photoconductive effect, which means that under the action of light, electrons absorb photon energy and transition from the bonded state to the free state, which causes a change in the conductivity of the material. That is, when light is irradiated on the photoconductor, if the photoconductor is an intrinsic semiconductor material, and the light radiation energy is strong enough, the electrons on the valence band of the photoelectric material will be excited to the conduction band, so that the conductivity of the photoconductor becomes Big. It refers to a physical phenomenon in which the conductivity of the irradiated material changes due to radiation. Photons act on the photoconductive material to form intrinsic absorption or impurity absorption, and generate additional photogenerated carriers, thereby changing the conductivity of the semiconductor, thereby Complete the conversion of light to electricity. The basic working mechanism of photodetector includes three processes: 1. Photogenerated carriers are generated under light; 2. Carrier diffusion or drift to form current; 3. The photocurrent is amplified and converted into a voltage signal in the amplifying circuit. When the detector surface is irradiated with light, if the forbidden band width of the material is less than the energy of the incident light photon, that is, <hv, the electrons in the valence band can jump to the conduction band to form a photocurrent. The development direction of photodetector self-driving photodetector In recent years, with the gradual scarcity of oil, natural gas and other resources, people have realized the importance of energy saving and carbon reduction, so the development of electronic components has put forward the requirement of low energy consumption. In this context, the concept of self-driven photodetectors was born. A self-driven photodetector refers to a device that responds to incident light and obtains a response current without the need for an external bias voltage. The principle is to use the built-in electric field of the pn junction or Schottky junction to separate electron-hole pairs, and drive the carriers to move to the electrodes, thereby forming a current. Self-driven photodetectors conform to the development trend of miniaturization, integration and low power consumption of electronic components, and have become the focus of research in recent years. The picture shows the principle schematic diagram of the new perovskite self-driven photodetector proposed by Professor Qu Junle of Shenzhen University and others on “Nano Energy”.

Application of Surface Plasmon Resonance Effect Using the surface plasmon resonance effect in the photodetector can effectively enhance the light absorption of the device, expand the light absorption spectrum of the device, thereby generating more electron-hole pairs, improving the response current of the device, and the resonance wavelength can be determined by the metal nanometer The dielectric environment of the structure, size and shape are changed, thereby tuning the absorption band. Regularly distributed metal nanostructures, such as hole arrays or grid lines, can interact with light, thereby improving the light absorption capacity of the device. In addition, it can be seen from the figure that there are a large number of freely oscillating electrons on the surface of the metal nanoparticles, and they have a certain frequency. When this frequency is equal to the frequency of the incident light, then the electrons on the surface of the metal nanoparticles Photons and electrons resonate in a localized area, which greatly enhances the light absorption of the device. The excitation conditions of the latter are relatively simple, that is, the size of the metal nanoparticles should be smaller than the wavelength of the incident light, and changing its size can adjust the resonance band, so it has better adjustability and more flexible application, and is widely used to enhance the performance of the device .

CMOS Compatible Silicon Waveguide Photodetector As an important class of photodetectors, silicon-based waveguide photodetectors have broad market application prospects in optoelectronic monolithic integration due to their compatibility with standard CMOS processes and simple fabrication processes. Since silicon-based photonics can utilize the microelectronics process lines that have been applied on a large scale, it has a good cost advantage and broad application prospects, especially in recent years, major foreign research institutions have made significant progress in this field . So far, a series of silicon photonic devices such as low-loss optical waveguides, optical attenuators , optical wavelength division multiplexing/demultiplexing devices, silicon lasers, etc. have been reported successively. In 2006, Intel and UCLA announced the successful research of the world’s first hybrid Si-InP laser. In 2022, Ye Peng, Xiao Han and others from Zhejiang University produced a Si-CMOS compatible 2D PtSe2-based self-driven photodetector with ultra-high responsivity and specific detectivity. This platinum diselenide/ultra-thin dioxide Photodetectors with silicon/silicon heterostructures have excellent properties such as high performance, air stability, self-driving, and room temperature broadband. The use of silicon device technology to make p-n and p-i-n diode photodetectors has long been realized. The peak response of this detector is about 700nm, which is suitable for the detection of 850nm band in optical communication; the disadvantage is that it cannot be applied Today’s optical communication band is 1550nm, which cannot realize the integration of microelectronics and optical circuits. One solution is to integrate the III-V detectors on the silicon integrated optical path by bonding; the other solution is to form deep-level defects through ion implantation, and use defect absorption to realize silicon pair 1550nm wavelength. detection. In recent years, the performance of silicon 1550nm photodetectors prepared by several foreign research institutions using this method has been greatly improved. In addition to introducing deep-level defects to make silicon-based photodetectors by ion implantation, methods such as Ge/Si heterojunction and AlGaInAs-Si hybrid integration are also common methods for making silicon-based photodetectors at home and abroad. Market Status Analysis of China and Global Photodetector Industry We combine the basic information of photodetector-related publications at home and abroad and the detailed information provided by photodetector industry research units, combined with in-depth market research data, based on the current global and Chinese macroeconomics, policies, and major industries. , and analyze and predict the development trend and prospects of the photodetector industry in the future. Global Market of Silicon-based Photodetectors Silicon-based photodetectors are referred to herein as silicon drift detectors (SDDs) and silicon photomultipliers (SiPMs). The main manufacturers of silicon-based photodetectors in the world include Hamamatsu, ON Semiconductor, Broadcom, First Sensor, AdvanSiD, etc., and the top five manufacturers in the world have a total market share of about 75%. North America is currently the world’s largest market for silicon-based photodetectors, accounting for about 40% of the market, followed by China and Europe, which together account for more than 35%. In 2020, the global silicon-based photodetector market will reach US$8.3 million, and it is expected to reach US$13 million in 2026, with a compound annual growth rate (CAGR) of 6.9% (2021-2027). At the same time, the scale of the Chinese market is growing rapidly, and the growth rate in the next six years is expected to be comparable to that of the global market. Spectrometer Photodetector Market Status And for the spectrometer photodetector market. The core manufacturers of Photodetector for Spectrometer in the world include Hamamatsu, trinamiX and InfraTec, etc., and the top three manufacturers account for about 50% of the global share. Similarly, North America is also the largest market in the world, accounting for about 40% of the market, followed by Asia-Pacific and Europe, both accounting for nearly 30%. From a product perspective, the near-infrared band is the largest segment with a share of about 30%, followed by the far-infrared band with a share of about 20%. In terms of application, medical is the largest downstream market, accounting for about 40% of the market, followed by food, accounting for about 20% of the market. To sum up, the author believes that with the advancement and development of science and technology, the importance of photodetectors in China will increase year by year, and the share of the Chinese market in the global photodetector market will increase accordingly. In the domestic market, The development prospects of new high-efficiency photodetectors represented by silicon-based photodetectors and CMOS-compatible III-V photodetectors are very broad. In the long run, it seems that China will occupy a place in the global photodetector market. and dreams. Advanced progress of world science and technology enterprises Intel High-Performance Silicon-Based Avalanche Photodetectors On December 7, 2008, Intel Corporation announced that its research team had made another major technological breakthrough in the field of silicon optoelectronics, successfully using a silicon-based avalanche photodetector (Silicon-based Avalanche Photodetector) to achieve a world record High performance, this avalanche photodetector achieves the highest ever “gain-bandwidth product” of 3 40G Hz using silicon and CMOS processes, which opens the door to reducing the cost of optical links for data transmission speeds of 40Gbps or higher, It also demonstrates for the first time that the performance of silicon optoelectronic components can exceed the performance of existing optoelectronic components fabricated using more expensive traditional materials such as indium phosphide (lnP). An emerging technology, Silicon Photonics, uses standard silicon to send and receive optical information between computers and other electronic devices. This technology can also be applied to future data-intensive computing fields such as telemedicine and 3D virtual worlds with high bandwidth requirements. Japan developed a high-performance 256×256 long-wave quantum dot infrared photodetector Quantum dot infrared photodetectors (QDIPs) have attracted extensive attention in recent years because they can be fabricated with mature conventional GaAs processes. Not only is it able to detect normal incident light, but it also works at higher temperatures. These are incomparable to quantum well infrared photodetectors (QWIP). The Electronic System Research Center of the Institute of Technology Research and Development of the Ministry of National Defense of Japan , in cooperation with Fushi Laboratory Co., Ltd., has developed a 256×256 pixel multilayer film with self-assembled quantum dots grown by molecular beam epitaxy. Long-wave infrared QDIP focal plane array The pixel interval of the infrared focal plane array is 40μm, the readout circuit adopts a direct injection input structure, the integration time is 8ms, the frame rate is 120Hz, the F number is 2.5, and the working temperature is 80K. To evaluate the performance of the infrared focal plane array, the researchers housed it in an integrated detector refrigerator assembly and measured its output at a temperature of 80K. The results show that the peak response wavelength of the array is 10.3μm, and the noise equivalent temperature difference is 87mK. CMOS Compatible III-V Photodetectors Researchers in Switzerland and the United States have been working to integrate III-V photodetector structures on silicon photonic integrated circuits (PICs). IBM Research Zürich, ETH Zürich and IBM T. J． A team at the Watson Research Center has developed a process that is compatible with mainstream complementary metal-oxide-semiconductor (CMOS) electronics fabrication. The active III-V structure consists of ten InAlGaAs compressed quantum wells grown on InP by metal-organic chemical vapor deposition (MOCVD) at 550°C. The structure is bonded to a Si-PIC wafer with an alumina bonding layer at temperatures below 300°C. The researchers tested the response of 2-μm-long photodetectors with stripe widths of 200nm and 300nm. 300nm wide equipment has 8． A 3dB bandwidth of 5GHz, compared to 1.5GHz for a similar device with direct contact. The 200nm device was tested under 1295nm optical signal modulation of the 100G Bd switch key, and the electro-optical bandwidth is about 65GHz. The researchers believe that tweaking the geometry of the device could increase the bandwidth to 100GHz. The team also performed a 100Gbit/s pseudorandom bit sequence OOK test, demonstrating a bit error rate (BER) of 1.9×10-3 through digital interpolation. The team commented: “This experiment was an eye-opener that multi-level modulation formats could be used, allowing higher capacities per channel.

epilogue It can be seen that photodetectors are not only widely used in the military field, but also widely used in civilian and daily life. They are closely related to our lives and provide great convenience for human life. However, some commonly used photodetectors , such as PbS, etc., due to its certain toxicity, it will cause damage to the human body and the environment, so the future development will be limited. Exploring a non-toxic and resource-rich material, optimizing its photoelectric performance, and applying it in the field of photodetectors will definitely bring greater blessings to mankind.