Electrical Properties of ZnO Thin Films Prepared by Sol-gel Technique

摘要

Zinc Oxide (ZnO) thin films were deposited on a glass substrate by sol-gel process dip-coating method. Zinc acetate dehydrate Zn(O_2 CCH_3)_2(H_2O_)2 are used as a starting material while 2-methoxyethanol (C_3H_8O_2) and monoethanolamine (MEA) are us ed as a solvent and stabilizer. The molar ratio of zinc acetate dihydrate to MEA is 1:1. The molarity of the solution and pre-heating temperature were kept constant at 0.4M and 150°C. Annealing temperature was fixed at 550°C but the withdrawal speed was varied from lmm/s to 9mm/s. The effects of withdrawal speed on electrical and surface morphology of the ZnO thin films have been investigated. The electrical and surface morphology properties of the ZnO thin films were characterized by I-V measurement and atomic force microscopy (AFM). The electrical measurement showed that current decrease when the withdrawal speed increases. High conductivity at 5.87×10 S/cm and lowest resistivity about 1.7×10~3 ft/cm have been obtained for lmm/s withdrawal speed. AFM micrographs showed average grain size of ZnO thin films increases from 120.862nm to 138.521nm with an increasing in withdrawal speed.