IMPROVEMENT OF THE CRYSTALLINITY AND OPTICAL PARAMETERS OF ZnO FILM WITH ALUMINUM DOPING

Bu çalışmada, katkısız ve alüminyum (Al) katkılı (%1 ve %3) çinko oksit (ZnO) filmleri cam alttaşlar üzerine spin kaplama tekniği ile sol jel metodu kullanılarak elde edilmiştir. Filmlerin yapısal ve optik özelliklerini incelemek için sırasıyla, X-ışınları difraktometresi ve UV-vis spektrofotometresi kullanılmıştır. Elde edilen filmler polikristal olup, hekzagonal wurtzite yapıda ve (002) tercihli yönelimine sahiptirler. ZnO filminin kristal kalitesi, artan Al katkısı ile artmıştır. Bu nedenle, en şiddetli (002) piki %3 Al katkılı ZnO filminde gözlenmiştir. UV-vis spektrofotometresine göre, filmlerin görünür bölgedeki ortalama transmittans ve reflektansları, sırasıyla %76 ve %14 değerinden büyüktür. Elde edilen filmlerin Al katkısına bağlı olarak absorpsiyon kenarlarını belirlemek için farklı metotlar kullanılmıştır. ZnO filminin optik bant aralığı, ilk Al katkısı ile mavi bölgeye kaymış, ve daha sonra Al katkı miktarı arttırılınca, kırmızı bölgeye kaymıştır. Kırılma indisi, sönüm katsayısı ve dielektrik sabitleri gibi optik sabitler katkısız ve Al katkılı ZnO filmleri için belirlenmiştir. Filmlerin kırılma indisi dispersiyonu, single oscillator model kullanılarak analiz edilmiştir. Elde edilen filmlerin osilatör enerjisi ve dispersiyon enerjisi gibi dispersiyon parametreleri belirlenmiştir

Anahtar Kelimeler:

Al katkılı ZnO filmleri, Sol jel, Optik bant aralığı, Optik sabitler, Dispersiyon parametreleri

IMPROVEMENT OF THE CRYSTALLINITY AND OPTICAL PARAMETERS OF ZnO FILM WITH ALUMINUM DOPING

In this study, the undoped and Aluminum (Al) doped (1% and 3%) zinc oxide (ZnO) films were prepared by sol gel method via spin coating onto glass substrates. To investigate the structural and optical properties of the films, it was used to X-ray diffractometer and UV-vis spectrophotometer, respectively. The prepared ZnO films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the (002) plane. The crystalline quality of ZnO film was improved by the increase of Al content. So, the most intense of (002) peak is observed for 3% Al-doped ZnO film. According to UV-vis spectroscopy spectra, the average optical transmittance and reflectance of all the films are greater than 76% and 14% in the visible range, respectively. The different methods were used to evaluate the absorption edges of the prepared films depending on the Al. The optical band gap value of ZnO film shifted towards to the blue region in the first incorporation of Al in ZnO film, and then, this value shifted towards the red region with increasing Al content. The optical constants such as refractive index, extinction coefficient and dielectric constants were determined for undoped and Al doped ZnO films. The refractive index dispersion of the films was analyzed by using the single oscillator model. The dispersion parameters such as oscillator energy and dispersion energy values of the prepared films were determined.

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