5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Impedance Studies On Aluminium Doped Sno2 Nanoparticles Synthesised By Sol-gel Process

Abstract: Metal oxides have been the subject of interest for the past few decades because of their unique properties. Some commonly used metal oxides are, ZnO, In2O3, CdO, SnO2, Al2O3. Stannic oxide (SnO2) remains a very active material in research till date due to its constructive properties for device fabrication [1, 2]. The performance of SnO2 based devices can be enhanced by tuning its structural, optical, electrical as well as the magnetic properties which can be achieved by means of adding suitable dopants such Tb3+, Eu3+, Ce3+, Dy3+, Mn2+, Al3+ etc., Addition of dopants and change in composition also affect the values of impedance and dielectric constant [3]. Electrical properties of metal doped SnO2 nanoparticles are dealt in very few literature works [1, 2, 4]. In the present work, the structural, optical and electrical properties of Al doped SnO2, i.e. Sn1-xAlxO2 (x varies as 0.2, 0.5, 1.0, 2.0 and 4.0 wt%) nanoparticles was studied and compared with that of undoped SnO2 nanoparticles. Since Aluminum is the most widespread metal on the Earth [5] and its ionic radii is comparable with that of Tin, it is chosen as the dopant. XRD study reveals that, on adding dopants, the crystallite size is reduced due to the dissolution of Al in the SnO2 lattice [1,6,7]. FTIR analysis confirmed the incorporation of Al in the SnO2 lattice. Impedance spectroscopic measurements were carried out in the temperature range from 34°C to 114°C over the frequency range of 7MHz to 50mHz. Along with the dc conductivity and ac conductivity studies, dielectric parameters and electric modulus parameters are investigated in detail as a function of frequency to find the suitability of the material in device applications. The non-linear behavior observed in the thermal dependence of the conductivity of Al doped SnO2 nanoparticles was explained by means of the defect states which modify the band structure on increasing the Al concentration [1]. Jonscher’s power law has been fitted for the conductance spectra and the frequency exponent (“s” value) gives an insight about the ac conducting mechanism. From the dielectric studies, it was noticed that in the frequency range of 150 Hz to 7 MHz, for doping concentration greater than 2.0wt% of Aluminium, the dielectric constant and dielectric loss values decrease to a greater extent of the order of 103 and 102 respectively than that of undoped sample whose values are 104 and 105 respectively. Further it was observed that the dielectric loss value remains almost invariant over a wide band width of frequency ranging from 150 Hz to 7 MHz. The undoped sample is seen to have the higher conductivity value (1.35E-04 S/cm) than the Al doped samples. Thus on proper doping of Aluminium, the electrical property can be tuned making it suitable for capacitor applications. The nature of relaxation time and beta values observed in the Complex electric modulus analysis confirmed the conductivity nature of the samples. Keywords: Al doped SnO2; Conducting mechanism; Impedance spectroscopy; Sol-gel process; Structural study. References: [1] Kumari N, Ghosh A, Bhattacharjee A. Investigation of structural and electrical transport mechanism of SnO2 with Al dopants, Indian J. Phys. (2014); 88(10):1059. [2] Mazumder N, Bharati A, Saha S, Sen D, Chattopadhyay K K. Effect of Mg doping on the electrical properties of SnO2 nanoparticles. Current Applied Physics (2012); 12:975. [3] Ammar A H, Abo Ghazala M S, M Farag A A, Eleskandrany A. Influence of composition on structural, electrical and optical characterizations of Bi48−xSbxSe52 ternary chalcogenide system. Indian J. Phys. (2013); 87: 1169. [4] Ameer Azam, Arham S. Ahmed, Chaman M, Naqvi A H. Investigation of electrical properties of Mn doped tin oxide nanoparticles using impedance spectroscopy. J. Appl. Phys. (2010); 108: 094329. [5] Starik A M, Savel’ev A M, Titova N S. Specific Features of Ignition and Combustion of Composite Fuels Containing Aluminum Nanoparticles (Review). Combustion, Explosion, and Shock Waves, (2015); 51(2):197. [6]. Venkateswara Reddy P, Venkatramana Reddy S, Sankara Reddy B. Structural and optical properties of co-doped (Fe, Al) SnO2 nanoparticles. International Journal of ChemTech Research, (2014); 7(3):1474. [7] Vanaja A, Ramaraju G V, Srinivasa Rao K. Structural and Optical investigation of Al doped ZnO Nanoparticles synthesised by Sol-gel Process. Indian Journal of Science and Technology. (2016); 9(12).
Sudha Periathai Ramamurthi, Pon Vengatesh Ramamurthi, Jeyakumaran Natarajan, Prithivikumaran Natarajan