Modeling of optical transmission through metal-oxide thin films
| Autor: | Petrović, Julia |
|---|---|
| Přispěvatelé: | Omerzu, Aleš, Peter, Robert, Jelovica Badovinac, Ivana, Kavre Piltaver, Ivna |
| Jazyk: | chorvatština |
| Rok vydání: | 2022 |
| Předmět: | |
| Popis: | Jedan od naˇcina prouˇcavanja optiˇckih svojstava tankih filmova je odredivanjem optiˇckih konstanti iz njihovih transmisijskih i apsorpcijskih spektara. U ovom radu su izmjerene transmitancija i apsorbancija tankih filmova titanijevog dioksida (TiO2) i cinkovog oksida (ZnO) debljina 50, 100 i 150 nm u rasponu valnih duljina od 200 do 1000 nm. Zbog koherencije valova dolazi do interferencijskog uzorka u mjerenim spektrima u slabo apsorbiraju´cem podruˇcju za oba materijala (od 400 nm do 1000 nm). Cilj ovog rada bio je modeliranjem izmjerenog transmisijskog spektra otkloniti utjecaj viˇsestrukih refleksija u tom podruˇcju. Odredio se teorijski model transmitancije za tanke filmove koji se potom prilagodio na dobivene rezultate u transparentnom podruˇcju. Zatim se ekstrapolirao na dio spektra u kojem dolazi do apsorpcije, tj. do 200 nm. Oduzimanjem mjerenog spektra i prilagodbe otklanja se utjecaj refleksije, gdje korigirani spektar sadrˇzi vjerodostojniju informaciju o podruˇcjima gdje je poluvodiˇc proziran i gdje dolazi do apsorpcije. Parametar debljine filma uzet je kao ocjena kvalitete prilagodbe, ˇcije su prave vrijednosti potvrdene snimanjem debljine filmova pretraˇznim elektronskim mikroskopom. Filmovi su narastani tehnikom depozicije atomskih slojeva, a transmitancija i apsorbancija mjerile su se UV-Vis spektrofotometrom. One way to study the optical properties of thin films is to determine the optical constants from their transmission and absorption spectra. In this work, the transmittance and absorbance of titanium dioxide (TiO2) and zinc oxide (ZnO) thin films with thickness of 50, 100 and 150 nm were measured in the wavelength range from 200 to 1000 nm. Due to the coherence of the waves, an interference pattern appears in the measured spectra in the weakly absorbing region for both materials (from 400 nm to 1000 nm). The aim of this work was to eliminate the influence of multiple reflections in this range by modeling the measured transmission spectrum. A theoretical model of the transmittance for thin films was determined, which was fitted to the results obtained in the transparent region. It was then extrapolated to the part of the spectrum where absorption occurs, i.e. up to 200 nm. Subtraction of the measured and fitted spectra removes the influence of reflection, where the corrected spectrum contains more reliable information about the spectral regions where the semiconductor is transparent and where absorption occurs. The film thickness parameter was taken as an assessment of the quality of the fit, whose true values were confirmed by imaging the film thickness with a scanning electron microscope. The films were grown using the atomic layer deposition technique, and the transmittance and absorbance were measured using a UV-Vis spectrophotometer. |
| Databáze: | OpenAIRE |
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