Effect of Erbium on Structural, Morphological and Optical Properties of Sol Gel Derived ZnO Film

Abstract

Undoped and Erbium (Er) doped zinc oxide (ZnO) films were prepared on p-Si substrates by sol gel method using spin coating technique. The effect of Er dopant on the structural, morphological and optical properties of ZnO film was investigated by X-ray diffractometer, scanning electron microscope (SEM) and UV-vis spectrophotometer, respectively. From X-ray diffraction (XRD) spectra, the films were crystallized in hexagonal wurtzite structure in zincite phase. The structural parameters such as grain size, dislocation density, lattice parameters, strain and stress were calculated. From the SEM images, it is seen that the film surfaces are well-coated, uniform, without cracks and pores. ImageJ program was used to investigate the average particle size, grain boundaries and the surface of the films. The optical properties were studied by diffuse reflectance spectra measured by UV-vis spectrophotometer and the optical band gap values were determined by differential reflectance and Kubelka-Munk theory. In both methods, it was determined the optical band gap value of ZnO film increases or decreases irregularly with the Er content. It was observed that the optical band gap of the 0.4% Er doped ZnO film was larger than the other films.

Keywords

• ZnO,Sol gel,SEM,XRD,Kubelka-Munk

Sol Jel Yöntemiyle Elde Edilen ZnO Filminin Yapısal, Morfolojik ve Optik Özelliklerine Erbiyum Katkısının Etkisi

Abstract

Katkısız ve Erbiyum (Er) katkılı çinko oksit (ZnO) filmleri sol jel spin kaplama yöntemi ile p-Si alttaşlar üzerine elde edilmiştir. ZnO filminin yapısal, morfolojik ve optik özellikleri üzerine Er katkısının etkisi sırasıyla, X-ışını kırınım cihazı, taramalı elektron mikroskobu (SEM) ve UV-vis spektrofotometresi kullanılarak araştırılmıştır. X-ışınları kırınımı (XRD) spektrumlarından, bütün filmlerin hekzagonal wurtzite yapıda ve zinkit fazda kristallendiği belirlenmiştir. Kristallenme boyutu, dislokasyon yoğunluğu, örgü parametreleri, kristal yapıdaki deformasyon ve gerilim gibi yapısal parametreler hesaplanmıştır. SEM görüntülerinden, film yüzeylerinin çatlaklar ve gözenekler olmadan iyi kaplanmış ve homojen olduğu görülmektedir. Ortalama tane boyutu, tane sınırları ve filmlerin yüzey durumlarının araştırılması için ImageJ programı kullanılmıştır. UV sprektrofotometresi ile optik ölçümler yapılmış ve optik bant aralığı diferansiyel yansıma ve Kubelka-Munk teorisiyle belirlenmiştir. Her iki yöntemden de, ZnO filminin optik band değerinin Er katkısıyla düzensiz olarak artıp azaldığı belirlenmiştir. %0,4 Er katkılı ZnO filminin optik band aralığının diğer filmlere göre daha büyük olduğu gözlenmiştir.

Keywords

• ZnO,Sol-Jel,SEM,XRD,Kubelka-Munk

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