INVESTIGATION OF ZNO:AL FILMS AS TRANSPARENT FRONT CONTACT FOR PHOTOVOLTAIC SOLAR CELLS

Abstract

In this work, doping with Al element (8% volume ratio) has been carried out to improve the physical properties of ZnO film used in photovoltaic solar cells. ZnO:Al films have been produced by ultrasonic spray pyrolysis technique and annealed in air to improve their physical characteristics. X-ray diffraction reveals that the films are polycrystalline having wurtzite hexagonal type crystal structure. Electrical resistivity values of the films have been increased after annealing process. Surface morphologies and roughness values of the films have been investigated by atomic force microscopy. Films are highly transparent in the visible region. Also, refractive index, n, and extinction coefficient, k, values for ZnO films have been reported. Optical band gap values have been determined using optical method. Finally, it has been concluded that annealing temperature has an important effect on the optical, structural, surface and electrical properties of the deposited films

Keywords

• Al doped ZnO, Optic properties, XRD, AFM, EDS

FOTOVOLTAİK GÜNEŞ PİLLERİNDE SAYDAM ÖN KONTAK OLARAK KULLANILABİLECEK ZNO:AL FİLMLERİNİN İNCELENMESİ

Abstract

Bu çalışmada, fotovoltaik güneş pillerinde kullanılan ZnO filminin fiziksel özelliklerini geliştirmek amacı ile Al elementi (% 8 hacimsel oran) ile katkılama işlemi yapılmıştır. ZnO:Al filmleri Ultrasonik Kimyasal Püskürtme tekniği ile üretilmiş ve fiziksel özelliklerini iyileştirmek için hava ortamında tavlanmıştır. X-ışını kırınımı analizleri filmlerin polikristal formda ve wurtzite hekzagonal tipi kristal yapıya sahip olduklarını göstermiştir. Elektriksel özdirenç değerlerinin tavlama işlemi sonrasında arttığı belirlenmiştir. Atomik kuvvet mikroskobu ile filmlerin yüzey morfolojisi ve pürüzlülükleri incelenmiştir. Filmlerin görünür bölgede yüksek geçirgenliğe sahip oldukları saptanmıştır. Ayrıca, filmler için kırılma indisi (n) ve sönüm katsayısı (k) değerleri de rapor edilmiştir. Filmlerin optik bant aralığı değerleri optik metot yardımı ile belirlenmiştir. Sonuç olarak, tavlama sıcaklığının elde edilen filmlerin optik, yapısal, elektriksel ve yüzeysel özellikleri üzerinde önemli bir etkisi olduğu saptanmıştır

Keywords

• Al katkılı ZnO, Optik özellikler, XIK, AFM, EDS

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