Influence of Tm2O3 doping on structural and electrical properties of ZnO

In this study, Tm2O3-doped ZnO powder system was synthesized in the stoichiometric range of 1-10 mol % by solid state method. Produced samples were characterized by XRD and monophase samples, which were indexed as hexagonal (wurtzite) structure, determined by using XRD data. The limit solubility of Tm2O3 in the ZnO lattice is determined to be 4 mol % (after heating at 1000 degrees C), and beyond 4 mol % the impurity phase was found as cubic-Tm2O3. For monophase Tm2O3-ZnO binary system (synthesized at 1000 degrees C), the lattice parameters a and c increased with Tm2O3 concentration. Electrical conductivity of undoped ZnO and monophase samples were measured using the four probe method. The electrical conductivity values of undoped ZnO and 4 mol % Tm2O3-doped ZnO samples (synthesized at 1000 degrees C) were found to be 8.7 x 10(-7) and 3.1 x 10(-6) Omega(-1) cm(-1), respectively, at 100 degrees C and 0.03 and 3.39 Omega(-1) cm(-1), respectively, at 1000 degrees C. Also, activation energy of monophase samples (synthesized at 1000 degrees C) was calculated. UV/Vis absorption and PL emission spectras of undoped and all doped ZnO samples were measured.