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  • Küçük Resim
    Öğe
    Investigation of nitrogen doped ZnO thin films: Effects on their structural and optical properties
    (Elsevier, 2021) Aydınoğlu, Hafize Seda; Hopoğlu, Hicret; Özer, Ali; ŞenadımTüzemen, Ebru
    Un-doped and nitrogen-doped ZnO thin films were grown by using radio frequency (RF) magnetron sputtering method changing the nitrogen flow rate between 0% − 12.5% and the thickness dependence of films was determined. The effect of nitrogen doping concentration on the structural, morphological, and optical properties of zinc oxide thin films was studied. X-ray diffraction (XRD) analysis confirmed that the nitrogen-doped ZnO films belong to the hexagonal crystal structure. The optical properties of the grown samples were examined by optical spectrophotometer and spectroscopic ellipsometer. Transmittance spectra were obtained by spectro photometer measurements and the effect of nitrogen ratio was investigated. It has been observed that as the nitrogen ratio increases, the transmittance decreases up to ~500 nm and then increases. By using the trans mittance curve, the energy band gap was calculated. Further detailed optical analysis was made by the spec troscopic ellipsometry technique. Fitting was performed to ensure the agreement between the experimentally obtained Ψ values and theoretically determined Ψ values using the Cauchy model. As a result, the refractive index was found for each film and it was observed that the refractive index decreased as the nitrogen ratio increased. The scanning electron microscopy (SEM) measurements showed that the surface morphology of the films changes with N doping. Nitrogen was observed in Fourier transform infrared spectra analysis. 5% nitrogen doped ZnO films were grown on the glass substrate using RF magnetron sputtering at room temperature. Samples are prepared by varying thicknesses during the deposition process. XRD and SEM measurements of the samples show the variation in the crystal structure and surface morphology of the film with varying thicknesses. All the samples are tested for the transmittance and band gap. The increase of film thickness increases the grain size. The transmittance is influenced by the film thickness.
  • Küçük Resim Yok
    Öğe
    Katkısız ve azot katkılı NiO ince filmlerin magnetron söktürme ile büyütülmesi, yapısal ve optik özelliklerinin incelenmesi
    (Sivas Cumhuriyet Üniversitesi, 2022) Hopoğlu, Hicret; Tüzemen, Ebru Şenadım
    Bu çalışmada, katkısız ve azot katkılı ince filmler farklı alttaşlar üzerine NiO hedefi kullanılarak farklı büyütme basıncı, farklı kalınlık, farklı alttaş sıcaklığı ve farklı miktarlarda azot katkısıyla RF magnetron söktürme yöntemi ile büyütülmüştür. Farklı büyütme şartlarında üretilmiş olan filmlerin kristal yapı, geçirgenlik ve enerji bant aralığı ayrıntılı olarak incelenmiştir. Bir p-tipi oksit yarıiletken olan Nikel oksit (NiO), çok yönlü ve ayarlanabilir özelliklerinden dolayı büyük ilgi görmektedir. Dirençli anahtarlama rastgele erişimli bellek cihazları ve son derece hassas ve seçici sensör uygulamaları dahil olmak üzere çok çeşitli elektronik uygulamalarında kritik malzemelerden biridir. Ek olarak geniş bant aralığından dolayı (NiO veya Ni(II) oksit, yüksek dirence, 3,6 – 4,0 eV'luk geniş bir bant aralığına sahiptir) NiO'yu yeni ortaya çıkan optoelektronik ve p-n heteroeklemlerde çalışmalarda yaygın olarak kullanılmaktadır. NiO ince filmlerin özellikleri büyük ölçüde depolama yöntemine ve koşullarına bağlıdır.