Type:
Journal
Description:
We have used confocal micro Raman spectroscopy, atomic force microscopy (AFM), and x-ray diffraction (XRD) to investigate pentacene films obtained by vacuum deposition on SiO 2 substrates. These methods allow us to follow the evolution of lattice structure, vibrational dynamics, and crystal morphology during the growth from monolayer, to TF, and, finally, to bulk crystal. The Raman measurements, supported by the AFM and XRD data, indicate that the film morphology depends on the deposition rate. High deposition rates yield two-dimensional nucleation and quasi-layer-by-layer growth of the TF form only. Low rates yield three-dimensional nucleation and growth, with phase mixing occurring in sufficiently thick films, where the TF form is accompanied by the “high-temperature” bulk phase. Our general findings are consistent with those of previous work. However, the Raman measurements, supported by lattice …
Publisher:
American Physical Society
Publication date:
8 May 2012
Biblio References:
Volume: 85 Issue: 19 Pages: 195308
Origin:
Physical Review B