Structural, optical and electrical properties of Hf-doped ZnO transparent conducting films prepared by sol–gel method

• Published in: Journal of alloys and compounds 2015-02, Vol.623, p.290-297
• Main Authors: Wang, Fenggui, Zhao, Xiaoru, Duan, Libing, Wang, Yajun, Niu, Hongru, Ali, Amjed
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum; Density; Electrical properties; Hafnium; Hf-doped ZnO; Optical properties; Photoluminescence; Resistivity; Sol gel process; Sol–gel method; Thin films; Zinc oxide
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.10.117

•Hf doping can enhance the crystallinity of ZnO significantly.•The ultraviolet emission band of HZO exhibits a blue shift.•The intensity of ultraviolet emission band rises with of Hf-doping density.•The resistivity of HZO film is 5.6×10−3Ωcm, which is lower than AlZnO film. Hafnium doped zinc oxide (HZO) thin films with various Hf contents (0, 1, 3, 5, 7at.%) at different solution concentrations (0.15–0.75mol/L) were deposited on the glass substrates using sol–gel method. The structural, optical and electrical properties were investigated by means of XRD, PL and Hall-effect measurement. The results show that Hf ions could substitute Zn ions effectively and improve the crystallinity of ZnO significantly with highly preferred c-axis orientation. Based on photoluminescence and transmittance measurements, the strong ultraviolet emission band exhibits a blue shift and its intensity is found to rise with the increasing of Hf-doping density. Furthermore, the resistivity shows a bell curve and the minimum value is 5.6×10−3Ωcm for the HZO film with 3at.% Hf, which is lower than that of the typical Al-doped ZnO thin films using sol–gel method.