Optical and magnetic properties of Sn_(1-x)Mn_xO_2 dilute magnetic semiconductor nanoparticles

摘要

Sn_(1-x)Mn_xO_2 (x = 0.05, 0.10 and 0.15) nanoparticles with tetragonal structure have been successfully synthesized by solvothermal method using oxalate precursor route. The oxalate precursors and its corresponding oxides were characterized by powder X-ray diffraction (PXRD), thermogravimetric (TG), fourier transform infrared (FTIR) and transmission electron microscopic (TEM) studies. PXRD studies showed the highly crystalline and monophasic nature of the solid solutions. The shifting of X-ray reflections towards higher angle is attributed to the incorporation of Mn~(2+) ions in SnO_2 host lattice. The average particle size was found to be in the range of 5-11 nm. Reflectance measurements showed blue shift in energy band gap which increases with increasing Mn~(2+) concentration. Surface area of these nanoparticles (59-388 m~2/g) was found to be high which increases with increasing the dopant ion concentration. Mn-doped SnO_2 showed distinct magnetic behaviour with different manganese concentration. Sn_(1-x)Mn_xO_2 {x = 0.05 and 0.10) revealed the parasitic ferromagnetism, however on increasing x = 0.15, sample showed paramagnetic behaviour.