A Study on the Structural, Morphological and Optical Properties of Cu2-xse Thin Films Deposited by Thermal Evaporation

Year 2021, , 1057 - 1063, 31.12.2021

Makbule Terlemezoğlu

https://doi.org/10.35193/bseufbd.1024354

Abstract

In this work, the influence of post-annealing on the structural, morphological, and optical properties of copper selenide thin films deposited on glass substrate by thermal evaporation was investigated in detail. The post-annealing process at different ambient temperatures in a nitrogen atmosphere was applied to thin films deposited at room temperature. The X-ray diffraction (XRD) patterns showed the presence of cubic Cu2-xSe phase, and it was observed that the crystallinity improves with increasing annealing temperature. In addition, it was deduced that the average crystallite size increased with the annealing temperature. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to investigate the surface morphology of thin films. It was seen that all samples have compact and densely packed surface morphology and grains on the surface become larger. Surface roughness increased from 11nm to 53 nm as the annealing temperature increased. On the other hand, the optical properties of as-deposited and annealed thin films were investigated by utilizing a UV-Visible spectrophotometer. The direct bandgap energies of as-deposited and annealed samples were estimated to be 2.34 eV, 2.31 eV, and 2.29 eV by using the well-known Tauc relation, respectively. The direct bandgap energy of thin films was also calculated using the derivative spectroscopy technique.

Keywords

Thin Film, Characterization, Post-annealing, Semiconductor, Thermal Evaporation

Supporting Institution

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Project Number

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Thanks

The author gratefully acknowledges Prof. Dr. Raşit Turan and Prof. Dr. Mehmet Parlak for using their facilities to carry out the measurements in the Center for Solar Energy Research and Applications (GÜNAM) in Middle East Technical University.

Termal Buharlaştırma ile Üretilen Cu2-xSe İnce Filmlerin Yapısal, Morfolojik ve Optik Özellikleri Üzerine Araştırma

Abstract

Bu çalışmada, termal buharlaştırma yöntemi ile cam alttaşlar üzerine kaplanmış bakır selenür ince filmlerin yapısal, morfolojik ve optik özelliklerine, üretim sonrası ısıl işlemin etkisi detaylı olarak araştırıldı.Oda sıcaklığında üretilen ince filmlere, azot gazı altında farklı sıcaklıklarda üretim sonrasıısıl işlem uygulandı. X ışını kırınım (XRD) deseni analizi, üretilmiş filmlerin kübik yapıda Cu2-xSe fazında olduğunu ve ısıl işlem sıcaklığı arttıkça filmlerin kristalleşme seviyesinin arttığnı gösterdi. Ayrıca, artan sıcaklıkla ortalama kristal boyutunun arttığı sonucu elde edildi. Filmlerin yüzey morfolojisini araştırmak için taramalı elektron mikroskobu ve atomik kuvvet mikroskobu kullanıldı. Filmlerin kompakt ve sıkı paketlenmiş yüzey morfolojisine sahip olduğu ve artan ısıl işlem sıcaklığı ile yüzeydeki tanelerin boyutlarının arttığı görüldü.Isıl işlem sıcaklığı arttıkça, yüzey pürüzlülüğü 11 nm’den 53 nm’ye yükseldi. Diğer yandan, üretilen ve ısıl işlem uygulanan ince filmlerin optik özellikleri, ultraviyole- görünür ışık spektrofotometrekullanılarakincelendi. Filmlerin direkt bant aralıkları, iyi bilinen Tauc bağıntısı kullanılarak sırasıyla 2.34eV, 2.31eV ve 2.29 eV olarak bulundu. Ayrıca, ince filmlerin direkt bant aralıkları türev spektroskopi tekniği kullanılarak da hesaplandı.

Keywords

İnce Film, Karakterizasyon, Üretim Sonrası Isıl İşlem, Yarıiletken, Termal Buharlaştırma

Project Number

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