Investigations of Crystalline Organic Nanostructures Grown by Ultra-High Vacuum and Vapor Phase Techniques.

摘要

We demonstrated the highly oriented growth of an organic salt using the new process of low pressure organic vapor phase deposition (LP-OVPD). This follows on our earlier work in the demonstration of atmospheric pressure OVPD. In the kinetic regime of LP-OVPD, however, there is improved surface morphology and crystalline alignment, to the point that we can now routinely achieve the alignment of DAST thin films across entire wafer surfaces. The material is excellent for optical modulators. We are currently investigating a modulator design which employs titanium dioxide waveguides coated with oriented DAST films. The wave propagating in the waveguide is evanescently coupled into the organic film which can be used to shift the phase of the wave by application (through electrodes) of an electric field. One milestone for the coming year is to demonstrate low voltage DAST-based phase modulators grown using LP-OVPD. This work is being published as an invited paper in Advanced Materials.