Molecular orientation of DHTAP on Cu(110) and the nanostructured Cu-CuO stripe phase

Description

The structure and orientation of 5,14-dihydro-5,7,12,14-tetraazapentacene (DHTAP) layers deposited on Cu(110), Cu(110)-(2x1)O and the Cu(110)/Cu(110)-(2x1)O stripe phase was studied using Reflectance Difference Spectroscopy (RDS) and Scanning Tunneling Microscopy (STM). The evolution of the RDS signal allows to identify the sequential formation of up to three monolayers as well as a phase transition upon completion of the first one. On Cu(110), DHTAP molecules in the first monolayer are always lying flat with their long molecular axis aligned parallel to the [-110]-direction of the Cu(110) surface [1]. However, for subsequent layers the orientation critically depends on the deposition temperature T. At T=240K the DHTAP molecules are mostly aligned parallel to the ones in the first layer, whereas at room temperature (RT) and above their preferential orientation is orthogonal to the molecules in the first layer. On Cu(110)-(2x1)O, DHTAP molecules in the first monolayer are aligned parallel to the [001]-direction. In contrast with the monolayer on Cu(110), the molecular orientation does not change for subsequent layers at RT.

Period	21 Feb 2024
Event title	unbekannt/unknown
Event type	Conference
Location	AustriaShow on map