INVESTIGATION OF THE ELECTRONIC CIRCUIT OF A DEVICE FOR ULTRAVIOLET RADIATION

ABSTRACT

In recent years, much attention in various fields of research has been paid to devices and photodetectors of the ultraviolet (UV) range with a wide range of industrial, military, biological and environmental applications. This paper focuses on the unique advantages of various UV-PDs, state-of-the-art device designs, and demonstrations, new structures, and new material compositions used to fabricate ultraviolet radiation devices.  In addition, we will consider many technical issues of designing electronic circuits of UV devices and compare the work of various designs of UV devices created to date, as well as analyze papers in various fields in which it is written about devices for UV radiation. Finally, we conclude this overview paper with some future lines of research in this area.

Keywords: UV (ultraviolet), semiconductor, light, device, photodetectors.

Introduction

Recent developments in broadband semiconductor technology have stimulated a great deal of interest in the application of UV potential. UV devices have many applications in areas such as engine control, solar UV monitoring, astronomy, lithographic aligners, safe interplanetary communications, or rocket detection [1]. In particular, UV-PD has attracted considerable attention in recent years due to the growth of new requirements of the civil and military industry to improve UV devices capable of operating at high temperatures and in harsh environmental conditions.

UV detection is commonly applied to semiconductor photodiodes, thermal detectors, photomultiplier tubes (PMTs), or charge-coupled devices (CCDs) because they have high gain and low noise and can be quite blind. The study of the electronic circuit of the device for ultraviolet radiation makes it possible to identify and correct several significant shortcomings, such as the bulkiness of the design, the small area of the radiating surface, low efficiency, high cost, and the presence of environmentally harmful substances. Also, this study will contribute to the process of further development and improvement of such devices.

In this paper, we look at recent advances in UV semiconductors / PDs, and it has focused on various advances that have been discussed in related papers.

Main part

The study of ultraviolet radiation is one of the most important tasks in the modern world. Ultraviolet radiation was discovered in 1801 by the German physicist Johann Wilhelm Ritter. Since then, it has been used in various fields. In the modern world, light sources are one of the most important things for human society, and the need for their consumption is growing every day. UV radiation is of great importance in such fields as medicine and biotechnology, ecology, materials science, flaw detection, criminology, astronavigation and astronomy, nuclear physics, telecommunications and energy. Currently, the world's leading manufacturers are developing UV photodetectors. These are photovoltaic multipliers of electron-optical converters, microchannel photocathode devices and devices based on broadband semiconductors.

Nowadays, various UV lamps are widely used in different fields depending on the purpose. For example, UV-C is used for germicidal purposes, especially in drinking water purifiers. UV-B and UV-A are used in many devices, including photocopying and phototherapy devices.

In the paper by V. A. Smirnov "Device for measuring the power of ultraviolet radiation", readers can get acquainted with devices for measuring UV, with technical solutions for measuring the intensity and dose of ultraviolet radiation. The biological effects of UV radiation are also considered here. The basis of the research was the assumption that ultraviolet radiation significantly affects the human body. The positive biological effects of UV radiation from the solar spectrum include a pigment-forming effect, an antirachitic effect, and a bactericidal effect. The spectrum of ultraviolet radiation is usually divided into such areas:1) A with a length of 400-315 nm; 2) B with a wavelength of 315-280 nm; 3) C with a length of 280 – 200 nm; 4) vacuum spectrum with a wavelength of 200-100 nm. This paper covers the first three ranges.

The authors found that there is a need for an accurate assessment of the intensity of UV radiation using appropriate devices. The scheme proposed by the authors is based on the ML8511 sensor manufactured by LAPIS Semiconductor. The paper presents the normalized spectral characteristics of the sensor and the basic electrical diagrams of the meter. Tests of the model sample showed that the developed device provides a measurement of parameters of ultraviolet radiation with a splitting capacity of 5 mW/m2 and an error of no more than 10 mW/m2. According to the authors, further improvement of the device is possible by introducing light filters for analyzing radiation by ranges, as well as by adding a memory module for recording changes in radiation intensity depending on time.

Physical principles of photodetection on natural diamond and prospects for the development of diamond photodetectors are considered in the paper by A. A. Altukhov, V. V. Eremin, V. A. Kireev, A.V. Mitenkin "Ultraviolet photodetector for the spectral range of 0.19-0.28 microns on natural diamond 2A".

The author examines the range of many applications for defense purposes. According to the authors, the spectral range of UV radiation for wavelengths less than 0.3 microns ("hard" ultraviolet), currently continues to be insufficiently studied. UV radiation shorter than 0.28 microns is quite strongly absorbed by the ozone layer of the atmosphere compared to visible radiation. UV radiation at λ ≥ 0.2 µm m is mainly absorbed by ozone. This is evidenced by studies of "ozone holes". Where there is no ozone, UV radiation from the Sun penetrates to the surface of the Earth. Multi-element photodetectors based on the natural diamond are considered an important factor. The author notes that the level of photovoltaic parameters of UV radiation receivers on natural diamond reaches values close to theoretically possible for the spectral range λ  = 0.19-0.28 microns. The studies of photodetector physics carried out by the authors allow us to hope that linear and matrix photodetectors operating on the principle of CCD can be created on natural diamonds.

The paper "Superior Deep-Ultraviolet Source Pumped by an Electron Beam for NLOS Communication" by Yongfeng Kang, Jingyi Zhao, Jiaxin Wu, Lei Zhang, Jian Zhao, Yiqi Zhang, Yuqing Zhao, and Xiaofei Wang explore deep ultraviolet radiation. As the author mentions, in comparison with traditional radio communication using long-wave electromagnetic waves, optical wireless communication has large frequency resources and noise immunity [2]. In particular, deep ultraviolet radiation (DUV) in the range of 200 to 280 nm, i.e. the area of ​​solar blindness, is receiving increasing attention due to its inherent advantages for communication over short distances, such as high local security, low background, and omnidirectional lines. communication. LEDs based on AlxGa1 - xN are attracting more and more attention since their emission band can be tuned in the range 210–365 Nm by adjusting the doping concentration of the Al component, as well as their compact size [3]. Researchers were also attracted by practical problems. This paper demonstrates a DUV source pumped by an electron beam (EB) at 246 nm with a record-high performance for NLOS communication, i.e. a simultaneous continuous output of 430 MW and a modulation frequency of 5 MHz. Significantly, both the output power and the modulation frequency can be further improved when the horsepower of the EBs is fully released. The proposed DUV source not only demonstrates great possibilities for NLOS communication and other potential applications, but the EB pumping approach can also be extended to various emission processes.

In conclusion, the author notes that a powerful and high-frequency light source DUV is experimentally realized by pumping fluorescent EB molecules. By judiciously controlling the voltage at each electrode, the radiation power can easily reach 430 MW at 246 Nm. Combined with the high modulation frequency of 5 MHz, the proposed DUV source could be a promising candidate for NLOS communications as well as other areas using DUV sources.

Questions related to the use of a new element base in some control and monitoring systems for large-scale objects, as well as the principles of constructing portable devices for monitoring ultraviolet radiation are considered in the paper by E. Vinogradova. "Portable devices for monitoring ultraviolet radiation." These are semiconductor metering sensors that give a quantitative result on a digital display or give a light or sound signal when a given dose of radiation is reached, and a dosimeter that measures the intensity of UV radiation or the dose received in real physical units.

This paper presents the results of the development of portable ultraviolet radiation monitoring devices based on a specialized semiconductor structure with negative differential resistance, developed at the Institute of Control Sciences of the Russian Academy of Sciences.

In the studied problematic, remote monitoring of industrial sources of UV radiation is indicated as the main aspects of the application. It detects, for example, the pre-breakdown state of high-voltage electrical equipment. Techniques such as corona and partial discharge registration are applied here. The results of the study allow us to practically be convinced that there are monitoring systems that require increased UV sensitivity. Such systems visualize ultraviolet radiation in real-time, in the external environment, and make it possible to obtain an image, for example, of a hydrogen flame and a corona discharge [4] The devices developed by the authors due to their simplicity and output signal parameters allow them to be used both in systems with a centralized architecture and a central server and in hierarchical systems with subsystems of different levels with their centers of processing and decision-making.

The devices proposed in this paper can be used both for self-monitoring and in combination with other sensors, if necessary. For example, in monitoring systems for social, natural, industrial facilities, territories, in large greenhouses and greenhouses, museums, hospitals, beaches, etc. Due to the widespread use of individual monitoring and UV monitoring devices in non-standard conditions, new requirements have appeared for the characteristics of such devices - diminutiveness, low cost, ease of use. Based on these criteria, it turned out to be promising to create UV control devices based on the above semiconductor sensor with a p + -n structure, one of the modifications of which is sensitive to UV radiation [5]. The research results show that such devices can be used for various types of control (current, preliminary, general, selective, comparative, informative, systematic, periodic, etc.) of ultraviolet radiation and irradiation according to a given program of data processing and control.

The next paper under review is titled “Evaluation of a Pulsed Ultraviolet Light-Emitting Diode for Triggering Photoconductive Semiconductor Switches” by Daniel Mauch, Cameron Hettler, William W. Sullivan, Andreas A. Neuber, and James Dickens. The study program of this paper was aimed at identifying the impulse response characteristics of a commercial 365-nm ultraviolet light-emitting diode (UV LED) for triggering a 4H-SiC photoconductive semiconductor switch (PCSS). The author analyzes in detail and argues convincingly that the impulse response of these LEDs is important because of their potential as an optical source for triggering and driving various broadband SiC and GaN semiconductors [7],[8]. The impulse response of these LEDs is especially relevant for applications in pulsed power engineering because of the possibility of extending the benefits of optical isolation to broadband materials-based devices. The paper provides a circuit for controlling the current and pulse width in an LED array. During the study, the spectral characteristics of the UV LED were measured using time-resolved electroluminescence (TREL) spectroscopy. It should also be noted that the LED has been tested with continuous currents from 150 mA to 750 mA. We can see the optical output power, forward voltage, and conversion efficiency during continuous operation and a short pulse of 10 μs in the figures in the paper. It is concluded that a pulsed UV LED is considered an attractive and compact light source for driving broadband semiconductor switches for switching power supplies [9; 10].

Exposing electronic materials to vacuum ultraviolet radiation can significantly affect their structure and instrument reliability. This point of view is seen in the works of G. S. Upadhyaya, J.L. Shohet, and J. L. Lauer, in the paper “Monte-Carlo Simulation of the Effects of Vacuum Ultraviolet Radiation on Electronic Materials”. This paper discusses the stages of developing a model for the interaction of a VUV-semiconductor-insulator based on the well-known Monte Carlo method. The Monte Carlo method has long been recognized as a powerful method for performing computations that are usually too complex for the classical approach. As the authors note, this task has a high degree of complexity due to the randomness of different scattering angles, distances, and multiplicity of processes, so this method is ideal for this task. This work shows that the Monte Carlo simulation of UV radiation interacting with a semiconductor dielectric material (Si3N4) can accurately predict the charge density and hence the potential at the surface of the dielectric layer [11]. The surface potential on a dielectric was experimentally estimated by the authors using a method known as the contact potential difference (CPD) method. It also provides a comparison of simulation results with experimental data. The experimentally measured surface potentials on the dielectric are used to validate the simulation. Of the various processes that can occur when a photon hits an atom, they focused on the photoemission of an electron. As a result of the simulation, statistical information was obtained on the percentage of backscattering, absorption coefficient, depth of photon penetration, and electron transfer.

Mobile ultraviolet light sources are discussed by Zhaozheng Wang, Yunxu Shi, Fan Liu, Hao Wang, Xu Liu, Runtong Sun, Yijia Lu, Linhong Ji, Zhong Lin Wang, Jia Cheng in the paper "Distributed mobile ultraviolet light sources driven by ambient mechanical stimuli". The paper analyzed the electrical and optical characteristics of mobile UV radiation. The authors of this paper intensively studied the influence of design parameters on the intensity of ultraviolet radiation, such as the speed of the heating element, the length or diameter of the movable UV tube. Also, for further analysis of the characteristics of the glow discharge, the electron temperature and density of the glow discharge were studied by comparing simulation and experiment. The authors believe the Moblie-UV system will demonstrate tremendous innovation in UV generation approaches and scenarios, especially for applying UV in a large number of areas of no or poor electricity. One cannot but agree with the author of this paper because this can serve as a guide for optimization in the future.

The research was carried out by methods such as FR-TENG structural design, electrical and optical emission measurements, bacterial culture, and UV curing experiments. During the study, the electrical characteristics of the FR-TENG were verified in detail, to further analyze the characteristics of the Mobile-UV and optimize the efficiency of ultraviolet radiation. The output characteristics of the open-circuit voltage (VOC) and short circuit current (ISC) of 12 FR-TENG units were tested at various speeds. The figures given in this paper show that the more parts on the FRONT panel, the higher the short-circuit current due to the faster electron transfer. It is also seen that the open-circuit voltage is higher than 2000 V, which significantly exceeds the discharge state of the UV tube. Also, a structure of 12 blocks with the highest current and a sufficiently high voltage was adopted here, because the current plays a more important role than the voltage in the ultraviolet discharge. The paper mainly shows the specific structures of FR-TENG and conducted an electrical experiment with loading for a UV tube (5 mm in diameter and 50 mm in length). The results showed that the effective value of the load current increases with increasing speed. The maximum value appears at 400 rpm, reaching 110 MCA. With increasing rotation frequency, the discharge frequency in the UV tube increases, which leads to a significant decrease in the effective voltage value. The effect of load power on rotational speed was also studied. The experiment shows that the Mobile-UV load power will increase with increasing rotational speed. Ultraviolet light with a fundamental wavelength of 253 nm was used for sterilization. Then the effect on the absolute strength of the UV tube in terms of length and diameter was investigated. It has been observed by the authors that the photoelectric conversion efficiency for a UV tube will increase with increasing rotational speed.

Recent efforts in the field of UV-PDs have focused on promoting reliable, high-sensitivity, broadband, low-cost, and diverse functional devices. However, they still cannot replace silicon detectors in the short term due to poor reproducibility and reliability of the devices. There are still many opportunities for the development of broadband semiconductors and their applications in the field of FDs. The development of high-quality substrates for homoepitaxial growth is key to increasing their productivity and reducing costs.

Regarding this, we can consider the works of Sanjib Mondala, Chiranjib Ghosha, S.M.M. Dhar Dwivedi, Anupam Ghosha, Sushama Sushamac, Subhananda Chakrabarti, Aniruddha Mondala, which is very interesting and unusual. Тhe pарer is called “ An experimental and theoretical understanding of a UV photodetector based on Ag nanoparticles decorated Er-doped TiO2 thin film”. In this work, we studied the synthesis of Ag NPs on solgel spin-on fabricated ER: TiO2 TF by the GLAD (Glancing angle deposition) method based on thermal evaporation. It demonstrates the improved optoelectronic performance of NP-based plasmonic UV-PD compared to a conventional device. To study the optical characteristics of the samples, UV-visible and PL characteristics were carried out. The detectors Au / Er: TiO2 TF / Ag NPs / Er: TiO2 TF / p-Si were manufactured and the characteristics of current (I) - voltage (V), sensitivity and time characteristic of devices under ultraviolet excitation. High-temperature (420 K) I – V characteristics was used for the study. The sensitivity of the detectors was calculated based on the knowledge that the quantum efficiency of the TD depends on the absorption coefficient of the material, the thickness of the absorbing region in the device, and the wavelength of the incident photon [6]. They also calculated the quantum efficiency using the absorption of materials and thus calculated the sensitivity.

The study adopted a theoretical approach to calculating wavelength-dependent sensitivity for both devices. In addition, important parameters such as the photoconductivity coefficient, electron transit time, and electron mobility were calculated by simulating the experimental sensitivity curves of the devices. These parameters demonstrated an improvement in the UV regime for the plasmonic AP. The fast response time with short rise and fall times proves the superior performance of plasmonic AP. The results obtained in the paper indicate that plasmonic Ag NPs can change the surface texture of Er: TiO2 TF, where UV sensitivity and other characteristic parameters of the detector are enriched. Thereby, they confirm that this process can be used to meet the requirements of commercial UV photodetectors, which can be an alternative to the low sensitivity Si-based UV detector.

Conclusion

Summing up the review of the papers, it can be seen that there is a wide variety of research areas for UV radiation devices. In addition, it should be noted that the topics of the articles discussed above are very diverse. However, it does not fully reflect the full range of problems and research directions characteristic of modern ultraviolet radiation devices.

The variety of directions under consideration gives the basis that the range of applications of devices for the emission of ultraviolet light is wide. In recent years, edge and quaternary compounds have been used in UV-PD structures, which obtain high selectivity in wavelengths and coincidence of the grating with the substrate. Research on components II-IV and organic materials have attracted interest in the last few years since in the future they will open new stages in the development of PD. In addition, the ability of broadband APs to operate under extreme conditions opens up new markets for new technologies, and it becomes clear in the future that these APs are likely to be very promising areas for many commercial applications. For further work, I propose to deeply explore the application of ultraviolet radiation in the field of nonlinear communication (NLOS) in complex relief environments.

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