Improved structural ordering in sexithiophene thick films grown on single crystal oxide substrates

TL;DR

This study demonstrates improved molecular orientation and uniform growth in sexithiophene films on single crystal oxides using chamber heating, enhancing their structural and electrical properties for potential electronic applications.

Contribution

It introduces a chamber heating method that promotes standing-up molecular orientation and stable growth in thick sexithiophene films on oxide substrates.

Findings

Enhanced molecular orientation with chamber heating.

Uniform, step-like island morphology observed.

Charge transport depends on inter-island separation.

Abstract

We report on sexithiophene films, about 150nm thick, grown by thermal evaporation on single crystal oxides and, as comparison, on Si/SiO2. By heating the entire deposition chamber at 100 C we obtain standing-up oriented molecules all over the bulk thickness. Surface morphology shows step-like islands, each step being only one monolayer height. The constant and uniform warming of the molecules obtained by heating the entire deposition chamber allows a stable diffusion-limited growth process. Therefore, the regular growth kinetic is preserved when increasing the thickness of the film. Electrical measurements on differently structured films evidence the impact of the inter island separation region size on the main charge transport parameters.