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Influence of aluminium annealing on the galvanoluminescent properties of anodic oxide films

dc.contributor.advisorKasalica, Bećko
dc.contributor.otherZeković, Ljubiša
dc.contributor.otherPerić, Miljenko
dc.creatorSarvan, Mirjana Ž
dc.date.accessioned2016-01-05T12:51:22Z
dc.date.available2016-01-05T12:51:22Z
dc.date.available2020-07-03T09:50:06Z
dc.date.issued2012-06-29
dc.identifier.urihttp://eteze.bg.ac.rs/application/showtheses?thesesId=888
dc.identifier.urihttp://nardus.mpn.gov.rs/handle/123456789/3199
dc.identifier.urihttps://fedorabg.bg.ac.rs/fedora/get/o:7305/bdef:Content/download
dc.identifier.urihttp://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=44661519
dc.description.abstractRezultati spektralnih istraživanja predstavljeni u ovom radu prikazuju dva različita uzroka postojanja galvanoluminescencije: karboksilne jone koji su inkorporirani u oksidni film za vreme anodizacije i molekule AlH, AlO, Al2, AlH2 takođe formiranih tokom anodizacionog procesa i već prepoznatih u slučaju neorganskih elektrolita. Anodizacijom uzoraka u organskim elektrolitima, odgrejanih na temperaturama T ≥ 525 oC, GL spektar se takođe menja, dobija identičan oblik kao i onaj u neorganskim elektrolitima i za red veličine je veći od onih odgrejanih na T < 500 oC. Ova promena inteziteta GL je posledica, kao i u neorganskim elektrolitima, prisustva većeg broja i veličine zrnaca γ-alumine i ovaj mehanizam je dominantan u doprinosu inteziteta GL spektra. Analiza GL spektra dobijenog usled prisustva većeg broja zrnaca γ-alumine na površini uzorka, pokazuje da je on posledica elektronsko-vibracionih prelaza molekula: Al2, AlH, AlO, AlH2. Znajući da su Al2, AlO, AlH i AlH2 veoma nestabilni radikali u okruženju kakvo je u oksidnom sloju pri procesu anodizacije, predpostavljamo da nanopore predstavljaju mesta za njihovu egzistenciju i ekscitaciju sa elektronskom lavinom, nastale usled jakog električnog polja. U elektrolitima u kojima se stvaraju porozni oksidni slojevi, zrnca γ-alumine su izložena elektronskoj lavini sve dok su ta zrnca u barijernom delu oksidnog sloja. Dalji rast oksidnog sloja i stvaranje pora koje se dešava na granici metal-oksid dovodi do toga da termički stvorena zrnca γ-alumine prelaze u zidove pora što za posledicu ima gašenje GL. Zatim, prezentovan je galvanoluminescentni spektar dobijen u ultraljubičastoj oblasti za vreme anodizacije visokočistih aluminijumskih uzoraka odgrevanih na temperaturi iznad 525 oC. Naime, u dosadašnjim istraživanjima GL kao fenomena koji prati anodizaciju ventilnih metala, nisu primećeni efekti vezani za doprinos GL u UV oblasti za neodgrejane ili odgrevane uzorke ispod 500 oC, nego su dobijani signali reda šuma. Ranije je rečeno da temperaturski predtretman odgrevanja na temperaturi T ≥ 525 oC uzrokuje nagli porast broja i veličine kristalnih zrnaca γ-alumine, a to upravo dovodi do pojave GL i u UV oblasti optičkog spektra. Snimljeni GL spektar u UV oblasti je kontinualan sa jasno izraženom trakom u intervalu talasnih brojeva (32 100 - 34 800) cm-1 sa maksimumom na 313 nm (31 949 cm-1). Došlo se do zaključka da jasno izraženi maksimum na 313 nm pripada molekulu AlO i odgovara prelazu C2Π→X2Ʃ+ . Prilikom analize dobijenih spektara uzeta je u obzir i mogućnosti postojanja bliske trake koje odgovaraju prelazu A2Ʃ+→X2Π sistema OH, čije prisutvo ne može biti isključeno pri ovakvim eksperimentalnim uslovima. Najistaknutija traka (0-0) ovog elektronskog prelaza leži na oko 32 640 cm-1. Naime, osnovni vibracioni nivoi u X2Ʃ+ i C2Π stanjima za AlO su na 979 cm-1 i 856.5 cm-1 a dužine ravnotežne veze su 1.618 Å i 1.685 Å. Koristeći ove rezultate i, opet, harmonijsku aproksimaciju, dobijamo Franck-Condon-ove faktore za nisko postavljene vibracione prelaze u X2Ʃ+ i C2Π stanjima. U ovom slučaju je promena dužine veze značajnija nego u prvom slučaju za prelaz A2Ʃ+ →X2Π u molekulu OH. Posledica je da za Δ ν = ± 1, a za veće vrednosti ν čak Δ ν = ± 2 prelazi imaju intezitete koji se mogu porediti. Zbog ovoga je moguće očekivati kompleksniji spektar sa slabim lokalnim pikovima. Iz tog razloga smo pažnju usmerili na spektralni sistem AlO i prelaze X2Ʃ+ i C2Π . Da bi objasnili strukturu snimljenog pika, simulirali smo spektar koji se očekuje kao posledica elektronskog prelaza C2Π→X2Ʃ+ u molekulu AlO. Na osnovu brojeva iz tablica i termskih vrednosti, izračunali smo termske vrednosti za elektronsko stanje C2Π koje odgovara uočenim maksimumima traka. Može da se primeti da se rezultati simuliranog spektra slažu u svim pojedinačnim slučajevima sa odgovarajućim eksperimentalnim podacima (do na nekoliko cm-1). To je od veoma velike važnosti za unutrašnju konzistentnost i pouzdanu interpretaciju publikovanih eksperimentalnih rezultata. Samo u jednom slučaju, za granu R2 9-11, neslaganje je veliko i iznosi 23 cm- 1. Moguće je da razlog ovom neslaganju moguće je da leži u predisocijativnom ponašanju stanja C2Π. U ovom radu je takođe po prvi put: 1. Konstruisan i upotrebljen optičko-detekcioni sistem sa CCD kamerom kao detektorom za snimanje dinamike GL procesa u ultraljubičastoj oblasti spektra. 2. Urađena je kalibracja istog tog sistema, tj. određena kvantna efikasnosti celog sistema i zavisnost kolone piksela po talasnim dužinama za date položaje difrakcione rešetke.sr
dc.description.abstractThe results of spectral studies presented in this dissertation show two different causes for the existance of galvanoluminescence (GL) existence: carboxyl ions, which are incorporated in the oxide film during anodization and AlH, AlO, Al2 and AlH2 molecules which are also formed during the process of anodization and are already identified in the case of inorganic electrolytes. Anodization of the samples in organic electrolytes, annealed at temperatures T ≥ 525 °C, results in a change of GL intesity , given the identical form receives an identical shape as the inorganic electrolytes and an order of magnitude higher than those heated at T < 500 °C. This change intensity of GL is related toincreased number and size of grains of γ-alumina and this mechanism is the dominant contribution to the intensity of GL spectrum. This is confirmed in the case of inorganic electrolyte. Analysis of the GL spectrum obtained from the presence of a large number of grains of γ-alumina on the surface of the sample, shows that the spectrum is a consequence of electronic-vibrational transitions of molecules: Al2, AlH, AlO and AlH2. Knowing that the Al2, AlO, AlH and AlH2 are very unstable radicals in the oxide layer enviroment during the anodization process, we assume that the nanopores are places of their existence and excitation by the electron avalanche, caused by the strong electric field. In the electrolytes in which a porous oxide layers are formed, γ-alumina particles are exposed to electronic avalanche until the grains are part of the barrier oxide layer. Further growth of the oxide layer and pore creation on the metal-oxide interference causes the γ-alumina particles to transfer into the walls of the pores resulting in GL quenching. Subsequently, the GL spectrum obtained in the ultraviolet region during the anodization of high purity aluminum samples, annealed at temperatures above 525 °C is presented. It is important to mention that previous research results of the GL as a phenomenon that accompanies the anodization of valve metals showed no presence of GL in the UV region for either annealed or non-annealed samples. Thermal pretreatment by annealing at temperatures T ≥ 525 °C causes a sharp increase in the number and size of crystal grains of γ-alumina and it leads to GL in the UV range of the optical spectrum. Observed GL spectrum in the UV region is continuous with a well defined band in the range of wave numbers (32,100-34,800) cm-1 with a maximum at 313 nm (31,949 cm-1). It was concluded that clearly defined maximum at 313 nm belongs to the molecule AlO and it corresponds to C2Π→X2Ʃ+ transition. When the obtained spectrum was analyzed the possibility of close bands corresponding to transition A2Ʃ+→X2Π of system OH was taken into account.The presence of this transition can not be excluded under prepared experimental conditions. The most prominent band (0-0) of this electronic transitions lies at about 32,640 cm-1. The basic vibrational levels in X2Ʃ+ and C2Π states for AlO are at 979 cm-1 and 856.5 cm-1 and the equilibrium bond lengths are 1618 Å and 1685 Å. Using these results and the harmonic approximation, we obtain the Franck-Condon factors for the low vibrational transition placed in X2Ʃ+ and C2Π states. In this case the change in bond length is more important than in the first case of the transition A2Ʃ+ →X2Π in the OH molecule. The result is that for the Δ ν = ± 1 (or even higher) transitions have intensities that can be comparable. This makes it possible to expect a more complex spectrum with weak local peaks. For this reason, we focused our attention on the AlO spectral system and its X2Ʃ+ and C2Π transitions . To explain the structure of the observed peak, we simulated a spectrum that can be expected as a result of electronic transitions C2Π → X2Ʃ+ in the AlO molecule. Based on tabular and term values, we calculated values for term C2Π electronic state corresponding to the observed maximal bands. The results of the simulated spectrum agree in all individual cases with the corresponding experimental data (up to several cm- 1). This is of great importance for the internal consistency and a reliable interpretation of published experimental results. Only in the case of R2 9-11 branch, the disagreement is larger than stated and it is 23 cm-1.The reason for this discrepancy may be in predissociative behavior of the C2Π state. Other important results reported for the first time in this dissertation are: 1. Design, construction, and experimental validation of the new optical-detection system with CCD camera as a detector for capturing the dynamics of the GL process in the ultraviolet spectral range. 2. The calibration of the optical-detection system was performed, i.e. quantum efficiency of the whole system was determined, as well as the dependence of the column of pixels per wavelength for given positions of diffraction gratings.en
dc.formatapplication/pdf
dc.languagesr
dc.publisherУниверзитет у Београду, Физички факултетsr
dc.rightsopenAccessen
dc.sourceУниверзитет у Београдуsr
dc.subjectgalvanoluminescencijasr
dc.subjectgalvanoluminescenceen
dc.subjectanodizationen
dc.subjectγ-aluminaen
dc.subjectannealningen
dc.subjectAlOen
dc.subjectOHen
dc.subjectanodizacijasr
dc.subjectγ-aluminsr
dc.subjectodgrevanjesr
dc.subjectAlOsr
dc.subjectOHsr
dc.titleUticaj termičkog tretmana aluminijuma na luminescentne osobine anodnih oksidnih slojevasr
dc.titleInfluence of aluminium annealing on the galvanoluminescent properties of anodic oxide filmsen
dc.typedoctoralThesisen
dc.rights.licenseBY-NC-ND
dcterms.abstractКасалица, Бећко; Перић, Миљенко; Зековић, Љубиша; Сарван, Мирјана Ж; Утицај термичког третмана алуминијума на луминесцентне особине анодних оксидних слојева; Утицај термичког третмана алуминијума на луминесцентне особине анодних оксидних слојева;
dc.identifier.fulltexthttp://nardus.mpn.gov.rs/bitstream/id/24883/Disertacija.pdf


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