Güneş pilleri için ZnO'nun yapısal ve elektronik özelliklerinin incelenmesi: Ab-initio çalışması

Abstract

ZnO bileşiğinin kristal yapısı yoğunluk fonksiyonel teorisi (DFT) ile genelleştirilmiş gradyant yaklaşımı (GGA) kullanılarak yüksek hidrostatik basınç altında 100 GPa’ya kadar çalışıldı. Çevre koşullarında ZnO, uzay grubu P6₃mc olan wurtzite (B4) tipi yapıda kristalleşir. Bu yapı üzerine artan basınç uygulandığında, ZnO’nun B4 yapısı uzay grubu  olan NaCl (B1) tipi yapıya dönüşmüştür. Bu çalışmada elde edilen faz geçişinin deneysel sonuçlarla uyumunu araştırmak için toplam enerji ve entalpi hesaplamaları yapıldı. Bu hesaplamalar sonucu faz değişiminin 9 GPa civarında gerçekleştiği sonucuna varıldı. Bu sonucun literatür ile uyum içinde olduğu görüldü. Ayrıca ZnO’nun elektronik özellikleri de incelendi. B4 ve B1 yapıları için band aralıkları sırası ile 0.7 eV ve 1.95 eV olarak elde edildi.

Keywords

• Yapısal faz geçişi,DFT,ab-initio moleküler dinamik,güneş pili

Investigation of structural and electronic properties of ZnO for solar cells: An ab-initio study

Abstract

The crystal structure of the ZnO compound was studied up to 100 GPa under high hydrostatic pressure using the density functional theory (DFT) with the generalized gradient approximation (GGA). Under ambient conditions, ZnO crystallizes in wurtzite (B4) type structure with space group P63mc. When increased pressure is applied to this structure, the B4 structure of ZnO is transformed into the NaCl (B1) type structure, which is the space group . Total energy and enthalpy calculations were carried out to investigate the phase transition obtained in this study with experimental results. These calculations are the result of a phase change of around 9 GPa. This result was found to be in accordance with the literature. The electronic properties of ZnO have also been studied. B4 and B1 band gaps were 0.7 eV and 1.95 eV, respectively.

Keywords

• Structural phase transition,DFT,ab-initio molecular dynamics

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