Investigation of Structural Properties and Determination of Pole Figures of CIGS Thin Films Produced by Co-Evaporation Method

Abstract

In this study, CIGS thin films, which consist of quaternary element composition and are frequently used in electro-optical applications, were produced by the thermal co-evaporation method, and their structural and electrical properties were investigated. Surface and thickness analyze were performed with SEM and AFM systems, and detailed structure and texture analyzes were performed with the XRD system. By examining SEM and AFM images, histogram curves and their associated Gaussian fits were obtained. In SEM images, it was observed that there were clusters of different sizes on the film surface, and by examining the histogram graph, it was determined that these clusters were homogeneously distributed. The average surface roughness was 4.94 nm from the AFM images. When the histogram graphics obtained from AFM images were examined, it was determined that the structures causing the roughness were homogeneously distributed on the surface. XRD measurements of the produced films were taken in the 20˚-60˚ 2θ range, and it was determined that the films had tetragonal Cu(In0.5Ga0.5)Se2 structure and (112), (204/220) and (312/116) orientations. The pole figures obtained as a result of the texture analysis were gained and the experimental pole figures were compared with the recalculated theoretical pole figures. In addition, Hall effect measurements of the films were taken at 3 µA level at room temperature. As a result of the study, it was tried to determine the suitability of CIGS thin films produced by the thermal co-evaporation method for the production of high-efficiency CIGS solar cells.

Keywords

• CIGS
• Thin Film
• Co-evaporation
• Pole Figures

Aynı Anda Buharlaştırma Yöntemiyle Üretilen CIGS İnce Filmlerin Yapısal Özelliklerinin İncelenmesi ve Kutup Figürlerinin Belirlenmesi

Abstract

Bu çalışmada dörtlü element kompozisyonundan oluşan ve elektro-optik uygulamalarda sıkça kullanılan CIGS ince filmler, aynı anda termal buharlaştırma yöntemiyle üretilmiş, yapısal ve elektriksel özellikleri incelenmiştir. SEM ve AFM sistemleri ile yüzey ve kalınlık analizleri, XRD sistemi ile detaylı yapı ve doku analizleri gerçekleştirilmiştir. SEM ve AFM görüntüleri incelenerek histogram eğrileri ve bunlara bağlı Gaussian teğetleri elde edilmiştir. SEM görüntülerinde film yüzeyinde farklı boyutlarda kümelenmelerin olduğu görülmüş ve histogram grafiği incelenerek bu kümelenmelerin homojen şekilde dağıldığı belirlenmiştir. AFM görüntülerinden ortalama yüzey pürüzlülüğünün 4,94 nm olduğu görülmüştür. AFM görüntülerinden elde edilen histogram grafikleri incelendiğinde de pürüzlülüğe sebep olan yapılanmaların yüzeyde homojen dağıldıkları tespit edilmiştir. Üretilen filmlerin 20˚- 60˚ 2θ aralığında XRD ölçümleri alınmış, filmlerin tetragonal Cu(In0.5Ga0.5)Se2 yapısında ve (112), (204/220) ve (312/116) yönelimlerine sahip olduğu belirlenmiştir. Doku analizleri sonucunda elde edilen kutup figürleri çıkarılmış ve deneysel kutup figürleri ile tekrar hesaplanan teorik kutup figürleri karşılaştırılmıştır. Çalışmanın sonucunda deneysel kutup figürleri ile tekrar hesaplanan teorik kutup figürleri arasındaki benzerlik oranlarının, XRD ölçümlerindeki pik şiddetleri ile orantılı olarak değiştiği tespit edilmiştir. Üretilen CIGS filmine ait kristal yönelimlerinin şiddeti ve film düzlemi boyunca dağılımlarının homojenliği kutup figürlerinin analizi ile çalışılmıştır. Literatürde yüksek verimler elde edilmiş çalışmalardaki kristal yapılar ile kıyaslanarak verimli güneş gözelerini üretmede kullanılabilirliği tespit edilmeye çalışılmıştır. Filmlerin Hall etkisi ölçümleri oda sıcaklığında, 1,1 Tesla manyetik alan altında ve 3 µA akım seviyesinde alınmıştır. Üretilen CIGS ince filmin p tipinde olduğu görülmüş ve sırasıyla öz direnci ve taşıyıcı yoğunluğunun 3,33×102 Ω.cm ve 1,36×1011 cm-3 olduğu hesaplanmıştır.

Keywords

• CIGS
• İnce Film
• Aynı Anda Buharlaştırma
• Kutup Figürleri

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