Effect of B doping on optical, electrical properties and defects of ZnO films

• Published in: Journal of alloys and compounds 2016-08, Vol.676, p.135-141
• Main Authors: Mao, Caiying, Fang, Liang, Zhang, Hong, Li, Wanjun, Wu, Fang, Qin, Guoping, Ruan, Haibo, Kong, Chunyang
• Format: Article
• Language: English
• Subjects: B doped ZnO films; Crystal defects; Defects; Doping; Electrical properties; Optical band gap; Optical properties; Stress; Tensile stress; X-ray photoelectron spectroscopy; Zinc; Zinc oxide
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2016.03.157

Boron doped ZnO (BZO) films with B content in the range of 0–6 at.% were deposited on quartz glass substrates by RF magnetron sputtering technique. The effects of B doping content on microstructure, optical and electrical properties of BZO films were systematically investigated by XRD, SEM, AFM, XPS, PL, UV–vis–near infrared spectrophotometer and Hall-effect measurement, respectively. It is found that the crystal quality of ZnO films can be improved as B doping content increases to no larger than 4 at.% and will be deteriorated at higher B doping content. The grain size and surface roughness of the films reduce with the increase of B doping content. The BZO films exhibit tensile stress and the stress increases with B content. The transmittance of the BZO films is revealed to be 90% in the visible region. As the B doping content increases from 0 to 6 at.%, the optical band gap of BZO films enhances from 3.28 to 3.57 eV, which is found to increase linearly with the tensile stress in the films. The lowest resistivity of 1.58 × 10−3 (Ω cm) is obtained at 2 at.% B doping content. XPS and PL analyses demonstrated that B doping can promote the formation of defects of zinc interstitials (Zni) and oxygen vacancies (VO). •The relationship of band gap (Eg) and stress (σ) in BZO is deduced.•XPS and PL illustrate B doping can promote the formation of Zni and VO in BZO.•The lowest resistivity (1.58 × 10−3 Ω cm) is obtained at 2 at.% B content.