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

O (ne)dopuštenosti restriktivnih klauzula u ugovoru o licenci patenta

License Agreement represents a legal institute which performs the constitutive transport of industrial property rights or an instrument that allows the connection of subjects that create intellectual resources with those that have technical and economic means for their exploitation. Licensing of new, protected inventions and their exploitation contribute undoubtedly to the overall social development. The right to a patent guarantees its titular, for a certain period of time, the monopoly right to its exploitation, so that his titular right can be transferred to other persons under much more restrictive conditions than is usual for the transfer of other rights. A superior position of a licensor allows him to put the license acquirer in a more dependent position by entering different restrictive clauses that affect the freedom of economy and competitiveness at the licensee market into concerned License Agreement. Due to violation of free competition in the market certain restrictive clauses in Patent License Agreements are considered to be unenforceable from the standpoint of Competition law and, for the need of Legal certainty, they have to be suppressed at both national and international level.Ugovor o licenci predstavlja pravni institut kojim se vrši konstitutivni promet prava industrijske svojine, odnosno instrument kojim se omogućava povezivanje subjekata koji stvaraju intelektualna dobra sa onima koji raspolažu tehničkim i ekonomskim sredstvima za njihovo iskorišćavanje. Licenciranje novih, zaštićenih pronalazaka i njihovo iskorišćavanje nesumljivo doprinosi opštem društvenom razvoju. Pravo na patent garantuje svom titularu, za određeni vremenski period, monopolsko pravo njegovog iskorišćavanja, tako da titular svoje pravo može prenositi drugim licima pod znatno restriktivnijim uslovima nego što je to uobičajeno za prenos drugih prava. Superiorniji položaj davaoca licence omogućava mu da sticaoca licence stavi u što zavisniji položaj tako što se u predmetni ugovor o licenci unose različite restriktivne klauzule koje utiču na slobodu privredjivanja i konkurentnost na tržištu korisnika licence. Zbog narušavanja slobodne konkurencije na tržištu pojedine restriktivne klauzule u ugovorima o licenci patenta smatraju se nedopuštenim sa stanovišta prava konkurencije, te se zbog potrebe pravne sigurnosti, suzbijaju kako na nacionalnom, tako i na medjunarodnom planu

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

Comparison of gamma ray effects on EPROMs and E2PROMs

This paper compares the reliability of standard commercial Erasable Programmable Read Only Memory (EPROM) and Electrically Erasable Programmable Read Only Memory (E2PROM) components exposed to gamma rays. The results obtained for CMOS-based EPROM (NM27C010) and E2PROM (NM93CS46) components provide the evidence that EPROMs have greater radiation hardness than E2PROMs. Moreover, the changes in EPROMs are reversible, and after erasure and reprogramming all EPROM components restore their functionality. On the other hand, changes in E2PROMs are irreversible. The obtained results are analyzed and interpreted on the basis of gamma ray interaction with the CMOS structure

Integrated Educational System – Pure Experiment or Model for the Future

The use of the term "integrated" in the sphere of education always refers to higher education, namely the studies involving basic academic studies and master academic studies. However, in contrast to this notion of "integration," in Serbia a sui generis model of integrated education has been developed. The model goes beyond the scope of known structure of integration and spreads both vertically and horizontally. It gathers institutions at all levels of education – starting with preschool, elementary, secondary, high and higher school education, and ending with the doctoral studies. At first sight, this new legal solution resembles a kind of educational industry holding. Of course, such new system faces certain difficulties and misunderstandings, being pretty different from both the classic and modernistic one. This is quite an unusual system, both in legal terms and terms of organization and management. Some will look at it as an experiment, for which they do not know whether it would hold out the test of time, but those who have created it, consider it an educational model of the future. In this article, we present "Integrated Educational System for Social and Natural Sciences" from Belgrade, as a case study, explaining its structure, regulation, organization and characteristics, as well as the challenges it faces. Our intention is to share with the Conference participants the experience, thoughts and observations about such a remarkable venture and discuss the lessons learned. This work is licensed under a&nbsp;Creative Commons Attribution-NonCommercial 4.0 International License.</p

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

Uticaj zračenja na starenje solarnih ćelija

Široka primena fotonaponskih (PV) solarnih sistema nameće potrebu izrade solarnih ćelija od različitih materijala i struktura u cilju poboljšanja njihovih osobina i smanjenja cene solarnih ćelija i struktura. Iako efikasnost pojedinih savremenih solarnih ćelija baziranih na pn spoju, u laboratorijskim uslovima dostiže 25% (što je blizu teorijskog maksimuma od 31%), dalje poboljšanje osobina ovih uređaja danas predstavlja glavni preduslov njihove šire upotrebe. Poslednjih godina, tržište fotonaponskih uređaja je izuzetno napredovalo, uz godišnji rast od oko 30% godišnje (u poslednjih 5 godina). Iz tog razloga je proučavanje spoljašnjih činilaca koji utiču na osobine solarnih ćelija, dovodeći do pogoršanja njenih osnovnih parametara od izuzetnog značaja. U ovom radu prikazani su rezultati dobijeni analizom uticaja zračenja na starenje, pa samim tim i na kvalitet solarnih ćelija kao fotonaponskih generatora

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