Increased temperature and radiation damage influence on solar cells characteristics

Mogućnosti primene solarnih sistema baziranih na fotonaponskoj konverziji solarne energije su veoma široke, prvenstveno zbog njene relativno niske cene, kao i veoma važne činjenice da solarna energija predstavlja najprihvarljiviji izvor električne energije sa stanovišta zaštite čovekove okoline. Solarne ćelije, osnovni element konverzije solarne energije su posebno osetljive na povišenu temperaturu i radijaciona oštećenja, prvenstveno zbog njihove velike površine. Degradacija električnih i optičkih karakteristika solarnih ćelija kao foto detektora u uslovima povišene temperature je jedan od najvažnijih ograničavajućih faktora za njihovu primenu. S obzirom na to da većina električnih procesa u poluprovodničkim uređajima, u izvesnoj meri zavisi od temperature, istraživanja na temperaturama višim od sobne mogu da otkriju moguće promene izlaznih karakteristika uređaja. Takođe, radni vek solarne ćelije je ograničen stepenom radijacionih oštećenja. To je zvačajan faktor koji utiče na rad solarne ćelije u praktičnoj primeni. Uvođenje radijacijom indukovanih rekombinacionih centara smanjuje se vreme života nosilaca u baznom sloju p-n spoja povećavajući rednu otpornost, što dovodi do izrazitog porasta šuma kod solarnih ćelija. Posle primljenih veoma velikih doza zračenja, redna otpornost baznog sloja može biti toliko velika da veći deo snage koju uređaj proizvede može da se disipira njegovom sopstvenom unutrašnjom otpornošću. Cilj ovog rada je da prouči uticaj povišene temperature i zračenja na izlazne karakteristike solarnih ćelija kao energetskog izvora budućnosti.Possibilities for the application of solar systems based on photovoltaic conversion of solar energy are very wide, primarily because of their relatively low cost and very important fact that solar energy is most acceptable source of electrical energy from the environmental point of view. Solar cells, the basic elements for photovoltaic conversion of solar energy, are especially susceptible to high temperatures and radiation damage, primarily due to their large surface. Degradation of electrical and optical characteristics of the solar cells as photo detectors in the increased temperature conditions is one of the most important limitation factors for their application. Since most of the electrical processes in semiconductor devices depend, to some extent, on the temperature, investigations at temperatures higher than room temperature may reveal possible changes in output characteristics of the device. Also, the lifetime of the solar cell is restricted by the degree of radiation damage that the cell receives. This is an important factor that affects the performance of the solar cell in practical applications. Introduction of radiation-induced recombination centers reduces the minority carrier lifetime in the base layer of the p-n junction increasing series the resistance, and lead to an enormous increase of noise in solar cells. After very high doses of radiation series resistance of the base layer could be so high that most of the power generated by the device is dissipated by its own internal resistance. The aim of this paper is to investigate the influence of high temperature and radiation on output characteristics of solar cells as power generators of the future

Comparative study of gamma and neutron irradiation effects on the silicon solar cells parameters

Zbog širokog područja primene, solarne ćelije su, u svom radnom okruženju, izložene različitim vrstama zračenja (kosmičko zračenje u gornjim slojevima atmosfere, vojna i civilna nuklearna postrojenja). Štaviše, korišćeno nuklearno gorivo u isto vreme emituje i u fotone i neutrone tako da se u solarnim ćelijama smeštenim u blizini ovih goriva javljaju različite vrste radijacionih oštećenja. Ova oštećenja su uzrokovana i gama i neutronskim zračenjem. Zbog toga su preduzimana vrlo opsežna istraživanja sa ciljem razvoja poluprovodničkih uređaja čiji rad će biti pouzdan i u uslovima povećanog nivoa zračenja. Sa tehnološkog aspekta, važno je utvrditi promene, uzrokovane zračenjem, u parametrima solarnih ćelija koje utiču na njihov rad. Cilj ovog rada je da se predstavi uporedna studija efekata gama i neutronskog ozračivanja na parametre solarnih ćelija.Due to its wide application areas, solar cells are exposed, in their work environment, to different types of radiation (cosmic radiation in the upper layers of the atmosphere, military and civilian nuclear facilities). Moreover, the used nuclear fuel emits y photons and neutrons at the same time, so different types of radiation damage appeared in solar cells located in the vicinity of these fuels. These damage have been caused by both gamma and neutron radiation. That's why very extensive researches have been undertaken with the aim of developing semiconductor devices whose work will be reliable in terms of increased levels of radiation. From the technological point of view, it is important to determine changes, caused by radiation, in the parameters of the silicon solar cells that affect their work. The aim of this paper is to present the comparative study of gamma and neutron irradiation effects on the solar cells parameters

The Impact of Successive Gamma and Neutron Irradiation on Characteristics of PIN Photodiodes and Phototransistors

The aim of this paper is to explore the impact of increased gamma and neutron radiation on the PIN photodiodes and phototransistors and their output characteristics. Special attention was paid to the successive impact of gamma and neutron radiation when the components were located in the field of gamma radiation and after that in the field of neutron radiation. The impact of successive irradiation was compared with the influence of gamma and neutron radiation when they appear individually. An important result of this research is the observation that neutron irradiation of photovoltaic detectors, applied after gamma irradiation, leading to partial reparations of distorted semiconductor structure and increasing disrupted output characteristics (photocurrent, spectral response). Monte Carlo simulation of gamma photons transfer through the crystal lattice of the semiconductor has been shown that the cause of such effect of neutron radiation is a large number of divacancies caused by successive operation of the previous gamma radiation and the neutron radiation itself. Divacancies have created the basis for increased generation of charge carriers by direct transfer (tunneling) of carriers through the traps (recombination centers). This is so called intercenter charge transfer

Comparative study of gamma and neutron irradiation effects on the silicon solar cells parameters

Zbog širokog područja primene, solarne ćelije su, u svom radnom okruženju, izložene različitim vrstama zračenja (kosmičko zračenje u gornjim slojevima atmosfere, vojna i civilna nuklearna postrojenja). Štaviše, korišćeno nuklearno gorivo u isto vreme emituje i u fotone i neutrone tako da se u solarnim ćelijama smeštenim u blizini ovih goriva javljaju različite vrste radijacionih oštećenja. Ova oštećenja su uzrokovana i gama i neutronskim zračenjem. Zbog toga su preduzimana vrlo opsežna istraživanja sa ciljem razvoja poluprovodničkih uređaja čiji rad će biti pouzdan i u uslovima povećanog nivoa zračenja. Sa tehnološkog aspekta, važno je utvrditi promene, uzrokovane zračenjem, u parametrima solarnih ćelija koje utiču na njihov rad. Cilj ovog rada je da se predstavi uporedna studija efekata gama i neutronskog ozračivanja na parametre solarnih ćelija.Due to its wide application areas, solar cells are exposed, in their work environment, to different types of radiation (cosmic radiation in the upper layers of the atmosphere, military and civilian nuclear facilities). Moreover, the used nuclear fuel emits y photons and neutrons at the same time, so different types of radiation damage appeared in solar cells located in the vicinity of these fuels. These damage have been caused by both gamma and neutron radiation. That's why very extensive researches have been undertaken with the aim of developing semiconductor devices whose work will be reliable in terms of increased levels of radiation. From the technological point of view, it is important to determine changes, caused by radiation, in the parameters of the silicon solar cells that affect their work. The aim of this paper is to present the comparative study of gamma and neutron irradiation effects on the solar cells parameters

The Impact of successive gamma and neutron irradiation on sharacsteristics of PIN photodetectors and phototransistors

The aim of this paper is to explore the impact of increased gamma and neutron radiation on the PIN photodiodes and phototransistors and their output characteristics. Special attention was paid to the successive impact of gamma and neutron radiation when the components were located in the field of gamma radiation and after that in the field of neutron radiation. The impact of successive irradiation was compared with the influence of gamma and neutron radiation when they appear individually. An important result of this research is the observation that neutron irradiation of photovoltaic detectors, applied after gamma irradiation, leading to partial reparations of distorted semiconductor structure and increasing disrupted output characteristics (photocurrent, spectral response). Monte Carlo simulation of gamma photons transfer through the crystal lattice of the semiconductor has been shown that the cause of such effect of neutron radiation is a large number of divacancies caused by successive operation of the previous gamma radiation and the neutron radiation itself. Divacancies have created the basis for increased generation of charge carriers by direct transfer (tunneling) of carriers through the traps (recombination centers). This is so called intercenter charge transfer

Effects of radiation on solar cells as photovoltaic generators

he growing need for obtaining electrical energy through renewable energy sources such as solar energy have lead to significant technological developments in the production of the basic element of PV conversion, the solar cell. Basically, a solar cell is a p-n junction whose characteristics have a great influence on its output parameters, primarily efficiency. Defects and impurities in the basic material, especially if located within the energy gap, may be activated during its life time, becoming traps for optically produced electron-hole pairs and, thus, decreasing the output power of the cell. All of the said effects could be induced in many ways over a life time of a solar cell and are consistent with the ef ects that radiation produces in semiconductor devices. The aim of this paper is to investigate changes in the main characteristics of solar cells, such as efficiency, output current and power, due to the exposure of solar systems to different (hostile) radiation environment

Probabilistic analysis of voltage divider ratios

Tolerancija modernih otpornika obično varira od 0.1% do 1 %. Sa probabilističke tačke gledišta to znači da se odgovarajući otpor može posmatrati kao slučajna promenljiva sa odgovarajućom funkcijom gustine raspodele verovatnoće (PDF). Dobijen je izraz za PDF za odnos prenosa dvo-otporničkog razdelničkog napona, kada je otporima u razdelniku dodeljena uniformna raspodela. Grafikoni dobijeni analitičkim izrazima, za različite kombinacije nominalnih otpora i tolerancije dvaju otpornika, upoređeni su sa onima dobijenim numeričkim simulacijama. Asimetrični karakter dobijenog rezultantnog PDF-a, uzrokovan nelinearnošću funkcije razdelničkog kola, implicira da se nominalna, srednja i najverovatnija vrednost razdelničkog odnosa mogu razlikovati. Za normalnu raspodelu otpora u dvootporničkom razdelniku, analitički pristup postaje složen, dok Monte Karlo simulacije lako daju grafikone naponskih odnosa PDF-a i izračunavaju vrednosti njihovih parametara.Tolerance of modern resistors typically ranges from 0.1% to 1%. From the probabilistic viewpoint, this is taken to mean that the corresponding resistance can be treated as a random variable, with an appropriate probability density function (PDF). We derive an expression for the PDF of a two-resistor voltage divider's transfer ratio, when the resistances in the divider are assigned uniform distributions. Plots of the obtained analytical expression, for various combinations of nominal resistances and tolerances of the two resistors, are compared to those produced by numerical (Monte Carlo) simulations. The asymmetrical character of the obtained resultant PDF, caused by non-linearity of the divider's circuit function, implies that the nominal, the mean and the most probable value of the divider's ratio can all differ. For normally distributed resistances in the two-resistor divider, analytical approach becomes complex, while Monte Carlo simulations readily provide the plots of voltage ratio PDFs and calculate the values of their parameters

Successive Neutron and Gamma Irradiation and Their Impact on the Characteristics of Solar Cells

This study investigates the effects of successive neutron and gamma radiation on the parameters of commercial solar cells. Several solar panels have been exposed to neutron radiation and then, after 30 days of recovery, to gamma radiation. A series of measurements of solar cell parameters have been undertaken to determine the reliability of solar cells in the condition of successive irradiation of different types of rays. Solar cell parameters have been measured before and after every step of irradiation. The process of annealing has also been observed. This paper aims to present the effects of both neutron and gamma radiation on the same solar cell sample

Probabilistic analysis of voltage divider ratios

Tolerancija modernih otpornika obično varira od 0.1% do 1 %. Sa probabilističke tačke gledišta to znači da se odgovarajući otpor može posmatrati kao slučajna promenljiva sa odgovarajućom funkcijom gustine raspodele verovatnoće (PDF). Dobijen je izraz za PDF za odnos prenosa dvo-otporničkog razdelničkog napona, kada je otporima u razdelniku dodeljena uniformna raspodela. Grafikoni dobijeni analitičkim izrazima, za različite kombinacije nominalnih otpora i tolerancije dvaju otpornika, upoređeni su sa onima dobijenim numeričkim simulacijama. Asimetrični karakter dobijenog rezultantnog PDF-a, uzrokovan nelinearnošću funkcije razdelničkog kola, implicira da se nominalna, srednja i najverovatnija vrednost razdelničkog odnosa mogu razlikovati. Za normalnu raspodelu otpora u dvootporničkom razdelniku, analitički pristup postaje složen, dok Monte Karlo simulacije lako daju grafikone naponskih odnosa PDF-a i izračunavaju vrednosti njihovih parametara.Tolerance of modern resistors typically ranges from 0.1% to 1%. From the probabilistic viewpoint, this is taken to mean that the corresponding resistance can be treated as a random variable, with an appropriate probability density function (PDF). We derive an expression for the PDF of a two-resistor voltage divider's transfer ratio, when the resistances in the divider are assigned uniform distributions. Plots of the obtained analytical expression, for various combinations of nominal resistances and tolerances of the two resistors, are compared to those produced by numerical (Monte Carlo) simulations. The asymmetrical character of the obtained resultant PDF, caused by non-linearity of the divider's circuit function, implies that the nominal, the mean and the most probable value of the divider's ratio can all differ. For normally distributed resistances in the two-resistor divider, analytical approach becomes complex, while Monte Carlo simulations readily provide the plots of voltage ratio PDFs and calculate the values of their parameters

Aging of the geiger-muller counter due to particle conductance in an insulating gas

In this paper, the aging effect of commercially available Geiger-Muller counters under working conditions is being considered from both theoretical and experimental point of view. In the experimental part lifetime curves for the commercial Geiger-Muller counter chamber are first recorded. After detection of the aging phenomena, the commercial chamber response to an impulse voltage is tested along with recording of the same response of the Geiger-Muller chamber model with conductive particles included. The law of similarity for the gaseous discharge is fulfilled both by the commercial Geiger-Muller chamber and by the chamber model with conductive particles. The results obtained from the U-test indicate that the aging of the Geiger-Muller chamber is mainly caused by the occurrence of a great number of conductive particles hovering inside the chamber. Some suggestions of how to reduce the aging effect due to conductive particles inside the Geiger-Muller chamber are given in the conclusion