Structural analysis and temperature dependent conductivity of LaxCu1-xO shrimp-like nanostructures synthesised via wet chemical precipitation

• Published in: Materials characterization 2020-12, Vol.170, p.110707, Article 110707
• Main Authors: Muiva, Cosmas, Lepodise, Lucia M., Bosigo, Romang, Juma, Albert
• Format: Article
• Language: English
• Subjects: Electrical conductivity; La-doped CuO nanostructures; Optical band gap; Wet chemical precipitation
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2020.110707

A series of well textured undoped and La-doped CuO (LaxCu1-xO, x = 0, 0.03, 0.06 and 0.10) nanostructures were synthesised via a low cost and facile wet chemical precipitation route. The structural, optical and temperature dependent electrical properties of the products were investigated and correlated. X-ray diffraction (XRD) showed formation of a pure phase of monoclinic CuO (undoped and 3–6 at.% La-dopped sample) and CuO-La2O2CO3 mixed phase in the higher doped sample (10 at.%). Scanning electron microscopy revealed shrimp like nanostructures of diverse sizes and aspect ratios for all the samples. The samples showed an optical absorption spectra with cut-off wavelengths lying in the visible spectral region. The temperature dependent electrical conductivity was measured and the trends depicted a typical semiconducting behaviour in all the samples. La doping of >3 at.% was associated with increased resistivity and premature levelling of the conductivity profiles at higher temperature. At 523 K, the electric field generated mobility and carrier concentration product values were observed to drop monotonously with doping. At room temperature the values were found to increase from 7.11 × 1014 (cm.s.V)−1 for the 0 at.% to peak at 2.16 × 1015 (cm.s.V)−1 for the 3 at.% and dropped to 8.95 × 1013 at 10 at.%. The conduction mechanism was explained on the basis of the hopping model. [Display omitted] •Nanostructures nucleate in an oriented lateral manner before growing into mesocrystals.•LaxCux-1O shows lowest activation energy for electrical conductivity for x = 6 at.%.•High doped LaxCux-1O exhibits the presence on La2C2O3 phases in the XRD diffractogram.•A blue shift in the absorption edge with increasing La dopant concentration is accompanied by an overall increase in transmittance in the visible region.