Synthesization of ZnO thin films by length controlled automatic sol-gel process

The aim of this work is to control the length of the substrate, which is covered by ZnO thin films by using a cost effective automatic sol-gel process. In conventional sol-gel process dipping and withdrawing is done manually, which can create vibration in the substrate while withdrawing/dipping. As a result the interference fringes will not remain constant and films thickness will be non-uniform. Moreover, it is a difficult task to maintain a constant dipping and withdrawing rate by hand. For the first time, an automatic sol-gel process has been introduced in this paper to overcome the drawbacks associated with the conventional sol-gel technique. The novelty of this work is to maintain constant speed during dipping/withdrawing substrate with the help of intelligent microcontroller and stepper motor. From this proposed system it is also possible to have a constant dipping and withdrawing rate (1cm/min). In this study, ZnO thin films have been deposited on different lengths of glass substrate (2-7 cm) by using the designed length controlled automatic sol-gel system. The surfaces of deposited films have been found uniform and the films have good transparency.