Pretreatment of Polyethylene Terephthalate Substrate for the Growth of Ga-Doped ZnO Thin Film

Abstract

The effect of the pretreatment of polyethylene terephthalate (PET) substrate on the growth of transparent conducting Ga-doped ZnO (GZO) thin film was investigated. Because of its high gas and moisture absorption and easy gas permeation, PET substrate was annealed at 100 degrees C in a vacuum chamber prior to the sputtering growth of GZO thin film for the outgassing of impurity gases. GZO thin film was deposited on the pretreated PET substrate by rf-magnetron sputtering and significantly improved electrical properties of GZO thin film was achieved. Electrical and structural characterizations of the GZO thin films were carried out by 4-point probe, Hall measurement, and scanning electron microscopy, and the effects of the pretreatment on the improved properties of GZO thin films were discussed. This result is not only useful to PET substrate, but also could be applicable to other plastic substrates which inevitably containing the moisture and impurity gases.

Interfacial Structure and Electrical Properties of Transparent Conducting ZnO Thin Films on Polymer Substrates

“…However, there have been some demerits regarding plastic substrates, such as weak interface between inorganic thin film and organic substrate, low thermal stability related to its high coefficient of thermal expansion (CTE), and easy permeation of moisture and oxygen molecules (MacDonald et al, 2005; Cheng & Wagner, 2009). Among these problems, there have been only few reports on the interfacial structure and the thermal stability of the impurity-doped ZnO thin film on the plastic substrate (Kim et al, 2010, 2011), whereas the barrier coating against the moisture and gas permeation has been extensively investigated by many research groups (Fortunato et al, 2002; Koidis et al, 2009).…”