Coverage dependent adsorption dynamics in hyperthermal organic thin film growth

Area of Science:

• Surface Science
• Materials Science
• Thin Film Growth

Background:

• Understanding molecular adsorption dynamics is crucial for thin film fabrication.
• Diindenoperylene (DIP) is a relevant organic semiconductor for electronic applications.

Purpose of the Study:

• To investigate the coverage-dependent adsorption dynamics of diindenoperylene (DIP) on SiO(2) surfaces.
• To explore the influence of interfacial organic layers on DIP adsorption.
• To elucidate the role of incident kinetic energy in the adsorption process.

Main Methods:

• In situ real-time synchrotron X-ray scattering was employed to monitor adsorption.
• Experiments were conducted on bare SiO(2) and organically modified SiO(2) surfaces.
• The effects of varying DIP coverage and incident kinetic energy were systematically studied.

Main Results:

• Adsorption probability significantly increases with DIP coverage on both surfaces.
• This effect is most pronounced at high incident kinetic energies.
• On initially bare surfaces, adsorption probability decreases with increasing kinetic energy, indicating trapping-mediated adsorption.
• At high DIP coverage, incident kinetic energy effects are reduced, and trapping becomes highly efficient.
• Efficient trapping at high coverage may involve mass matching for momentum transfer or direct molecular insertion.

Conclusions:

• Surface coverage is a critical factor governing hyperthermal adsorption dynamics of DIP.
• The observed behavior suggests efficient trapping mechanisms become dominant at high molecular coverages.
• These findings have implications for the controlled growth of organic thin films, potentially applicable to other small molecules like pentacene.