Impact of Al and Mn doping on structural and Electrical properties of the Green synthesized ZnO Nanoparticles

Undoped, Al and Mn doped ZnO nanoparticles (NPs) are synthesized from the combustion method using terminalia cattappa seeds extract, Zinc nitrate as precursor for both undoped and doped ZnO NPs synthesis, aluminium nitrate and manganese chloride are used as dopant for Al and Mn doped ZnO NPs respectively. Synthesized nanoparticles are characterized by XRD, FESEM, and FTIR. XRD studies show the formation of single phase hexagonal wrutzite structure and average crystallite size varies from 32.99 to 39.17 nm. Microstructural analysis is carried using FESEM and average grain is found to be 86.56, 77.36 and 101.46 nm for Undoped, Al and Mn doped ZnO NPs respectively. FTIR spectra show the Zn-O stretching band at 450, 440 and 540 cm
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for Undoped, Al and Mn doped ZnO NPs. From the UV-Vis spectroscopy energy band gap is determined which is found to be 3.25, 3.23 and 3.26 eV respectively. By using LCR meter dielectric constant and ac conductivity are studied in the frequency range from 10Hz to 8 MHz and temperature from 50 to 350°C with a step of 50°C. Cole-Cole plot shows the single semicircle for Undoped, Al and Mn doped ZnO NPs which confirms the grain boundary resistance is dominated than the grain resistance. Al doped ZnO NPs shows increased conductivity and dielectric property when compared to Mn doped ZnO NPs and is suited for the memory devices and MEMS.