| Popis: |
Electrical conductivity of SnO2based oxides is of great importance for their application as transparent conducting oxides (TCO) and gas sensors. Undoped and doped tin oxides were synthesized by simple gel combustion method and characterized by XRD, EDAX and SEM.The XRD pattern shows that pure and Mn doped SnO2in the tetragonal rutile-type structure.The atomic compositions and surface morphology of prepared samples were confirmed by EDAX andSEM respectively. Up on doping with the Mna slightshift in the diffraction peak to the higher angle and slight variation in the unit cell parameters were observed.The influence of Mn dopant on structural andDC conductivity of SnO2was studied.As compare with the doped tin oxide, pure exhibits rapid variation in conductivity at high temperature regime. The conductivity decreases with the increase of Mn concentration since,(1) Dopingwith Mn introduces ions into the host lattice with a lower valence compared to Sn4+. (2) The substitution ofMn2+ for Sn4+ would enhance the ionized impurity scattering, which in turn decreases the mobility of the charge carriers. The activation energies EAH and EALare both increase with the Mn concentration. |
