Structure and electrical properties of Mg-doped ZnO nanoparticles

MgxZn1-xO (x=0.01-0.3) nanoparticles were synthesized by the sol-gel technique using solutions of Mg and Zn based organometalic compounds. The electrical properties of Mg doped zinc oxide (ZnO) were studied within wide temperature range from 300 to 500 K under the N2 gas flow (flow rate: 20 sccm) and in the frequency range from 40 Hz to 1 MHz for ac electrical measurements. The dc conductivities and the activation energies were found to be in the range of 10-9-10-6 S/cm at the room temperature and 0.26-0.86 eV respectively depending on doping rate of these samples. The ac conductivity was well represented by the power law Aωs. The conduction mechanism for all doped ZnO could be related to correlated barrier hopping (CBH) model. The complex impedance plots (Nyquist plot) showed the data points lying on a single semicircle, implying the response originated from a single capacitive element corresponding to the nanoparticle grains. The crystal structures of the MgxZn1-xO nanoparticles were characterized using X-ray diffraction. The calculated average particle sizes values of Zn1-xMgxO samples are found between 29.72 and 22.43 nm using the Sherrer equation. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)