Lutentium incorporation influence on ZnO thin films coated via a sol-gel route: spin coating technique

Pure and lutetium (Lu) incorporated zinc oxide (ZnO) thin films were deposited by a sol-gel route. The effect of Lu contribution on the properties of ZnO was examined in detail by means of XRD, AFM, SEM, UV-Vis spectrophotometer, and I-V measurements. The nano-sized ZnO:Lu samples had hexagonal wurtzite structure with c-axis (002) preferential orientation. The pure ZnO nano-particles homogeneously scattered on the film surface and this homogeneous particle distribution was deteriorated with Lu incorporation. Ohmic contacts to the ZnO:Lu films were formed using gold (Au) metallization schemes. As-deposited Au contacts exhibited linear current-voltage characteristics. The optical band gap for pure ZnO went up from 3.281 to 3.303 eV with low Lu contribution level up to 3 at.%, then it decreased with more Lu level. The Urbach energy was also studied and it was found that E-u depended on Lu incorporation level.