Effect of Sintering Temperature on the Characteristics of Zn0.99Li0.01O Thin Film on Si Substrate

Lithium-doped zinc oxide (Zn0.99Li0.01O) film was manufactured by the sol-gel method using uniform and stable solution of zinc acetate dehydrate and lithium acetate dehydrate in methanol. Films were deposited by spin-coating using spinner between 4500 and 5000 rpm on silicon substrates. The prepared samples were sintered at various temperatures (600 degrees C similar to 1000 degrees C) in the air. The structural, morphological, and optical properties of the prepared lithium-doped ZnO films were investigated. The XRD pattern of Zn0.99Li0.01O film demonstrated the hexagonal wurzite structure. However, new crystal phase was discovered at a sintering temperature of 800 degrees C. New peak was found near 2 theta = 22.6 degrees in XRD patterns. The peak is thought to be the (101) plan in SiO2 cristobalite structure. Moreover, another new crystal phase related to Li2SiO5 was occurred at a sintering temperature of 900 degrees C. From XRD analysis, it was confirmed that C axis was decreased and the stress was increased, as sintering temperatures was increased from 600 degrees C to 900 degrees C. In cathodo luminescence (CL) data, zinc oxide usually appears ultra violet and green emission. However, the green emission did not appear in all these samples used in this study. The ultra violet emission showed red shift from 600 degrees C to 800 degrees C in the CL spectrum as the sintering temperature was increased. The phenomenon of the red shift can be explained in Burstein-Moss effect. At sintering temperature of 700 degrees C, the intensity of ultra-violet emission was the largest and full width at half maximum (FWHM) was the smallest.