Transmission/absorption measurements for in situ monitoring of transparent conducting Ga:ZnO films grown via aqueous methods

Abstract

In this work, we devised a simple optical technique that allowed the nucleation and growth of Ga:ZnO films grown via aqueous synthesis at 90 °C to be studied in situ. Our two fold objective was to study the nucleation processes and to acquire real-time information of the film thickness. In doing so, the growth parameters (e.g. temperature, precursor concentration, and time) could be optimized to give the maximum yield, coupled with the ability to control the film thickness with a greater measure of precision and accuracy. We further demonstrated that such a degree of control could be used to fabricate transparent conducting electrodes of low sheet resistance (<10 Ω sq⁻¹) that meet the demands of photovoltaic applications. The electrical properties of the synthesized Ga:ZnO films and commercial Al:ZnO substrates showed comparable performance in dye-sensitized solar cells. This opened the possibility of a controlled low-cost aqueous route to fabricating high quality transparent conductor films that may well replace existing vacuum deposition techniques.