Structural, optical, magnetic and dielectric studies of SnO2 nano particles in real time applications

Abstract

Pure and Aluminium doped (x = 0.01, 0.02, 0.03, 0.04) SnO2 nano particles have been prepared by Sol Gel method. XRD studies confirm tetragonal structure of SnO2 and second phase peaks are absent. The obtained crystallite size of undoped SnO2 is 17.5 nm and with Al insertion Crystallite size reduced to 10 nm for Sn0.96Al0.04O2. FTIR data in the range of 550 cm−1–630 cm−1 confirms the vibration modes of SnOSn and SnO in SnO2 molecules. UV spectrum shows red shift due to the trapping of exitons by oxygen vacancies. In contrast to quantum confinement energy gap decreases from 3.7 eV for undoped SnO2 and to 2.91 eV for Sn0.97Al0.03O2 due to the band bending, which is the result of particle size reduction and then increases to 3.19 eV. This variation has been explained based on Burstein-Moss effect for Sn0.96Al0.04O2. Impedance studies of undoped and Al doped SnO2 samples have been investigated at room temperature and found that Sn0.97Al0.03O2 exhibits peculiar behaviour of having high dielectric constant, high A.C. conductivity, low dielectric loss and high theoretically calculated mobility among Al doped SnO2 samples. The data obtained from Vibration Sample Magnetometer shows typical conversion of magnetic nature of undoped SnO2 which is diamagnetic to paramagnetic in the case of Sn0.99Al0.01O2 and Sn0.98Al0.02O2 samples and to superparamagnetic nature for Sn0.97Al0.03O2 and Sn0.96Al0.04O2.