Surface morphology of organic thin films at various vapor flux

The surface morphology of the organic energetic material pentaerythritol tetranitrate (PETN) grown on silicon substrates has been investigated. The surface structure of the films reveal clearly differentiated morphologies which is dependent on the vapor flux. Dendrite crystals are formed with flux of 0.03 nm/s while the morphology shows a transition from dendrite branches to grain growth as the flux is increased to 0.3 nm/s. The deposition thickness did not show an obvious influence on the surface microstructure. Therefore, the deposition flux allows the production of PETN films with desired surface morphology in a controllable and reproducible way.