Effects of Solution Concentrations on Crystal Growth of Anthracene Thin Films on Silicon by Rapid Expansion of Supercritical Solutions (RESS) Using Carbon Dioxide

Abstract

We report on an investigation to the e ects of supercritical solution concentrations on the crystal morphology, crystallinity, growth rate, and number density of anthracene grains in thin lms on silicon substrates by rapid expansion of supercritical solutions (RESS) using carbon dioxide to examine the crystal growth mechanism of anthracene thin lms. (molar fraction; a threshold concentration) with a change in morphology of grains from dendritic to island-like. Although the number densities of island-like and dendritic grains increased almost linearly with the solution concentration, the trend in the number density of grains also changed at the threshold concentration, with the change in morphology from dendritic to island-like grains. The crystal growth of grains deposited on the substrate was dominant and most of the given supersaturation was consumed for the crystal growth of grains at solution concentrations lower than the threshold concentration. At solution concentrations higher than the threshold concentration, the crystal nucleation on the substrate was dominant and most of the given supersaturation was consumed for the crystal nucleation of grains, followed by the crystal growth of the grains.

JCEJ Outstanding Paper Award of 2015

“…Dioxide" by Tatsuya Fujii, Yuta Takahashi, and Hirohisa Uchida, Shinshu University (Fujii et al, 2015) Citation: In this paper, the effects of supercritical solution concentrations on the crystal morphology, crystallinity, growth rate, and number density of anthracene grains in thin films on silicon substrates by rapid expansion of supercritical solutions (RESS) using carbon dioxide are investigated in detail. From the results, the authors examine the crystal growth mechanism of anthracene thin films.…”

Deposition of tetracene thin films on SiO2/Si substrates by rapid expansion of supercritical solutions using carbon dioxide

“…The properties of thin films formed by RESS depend on the operating conditions, as well as on the geometry of the expansion device. In previous studies, 25,26) we examined the effects of operating conditions, such as substrate temperature, spray distance, and solution concentration, on the crystal morphology, crystallinity, and growth rate of anthracene thin films formed by RESS. However, we have not examined the electrical characteristics of the thin films, that is, a performance evaluation of thin films formed by RESS used as OTFT active layers has not been carried out.…”