Molecular organization in organic semiconductor thin films observed in real time

Abstract

Post-deposition molecular rearrangement in thin organic films is revealed by in situ real-time photoelectron spectroscopy during organic molecular beam deposition. Agreement between real time spectroscopy and Monte Carlo modeling confirms the role of nearest-neighbor molecular attraction in driving a time-dependent morphology for oriented films of tin phthalocyanine (SnPc) on a range of substrates. The time-dependent molecular self-organization occurs over timescales comparable to the growth rates and is therefore an important factor in the degradation of thin films of organic semiconductors typically considered for the fabrication of multilayer semiconductor devices. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775762]publishersversionPeer reviewe

Influence of polarity and hydroxyl termination on the band bending at ZnO surfaces

“…Other examples of the use of snapshot core level photoemission spectra to monitor changes in surface band bending on semiconductor surfaces are described elsewhere. 45,46 In addition, LEED measurements were also carried out in 50°C steps from RT to the highest heating temperatures. 2(a)-2(c)] is due to bulk oxygen, while the higher BE component (shifted to higher BE by 1.4 eV) is commonly attributed to surface hydroxyl groups.…”

Effects of idling time between depositions of organic layers and metal electrode in organic photovoltaic device

“…In the initial stage of BPhen deposition, the molecules are influenced by underlying C 60 layer. Further BPhen deposition initiates molecular reorientation which takes several ten minutes until compact structure forms [27]. This process is mainly generated by molecular dipole interaction, p-stacking interactions, and van der Waals forces.…”

“….etc. The final compact structure can efficiently prevent the metal diffusion [27,28]. The idling time and the reorientation process are expected to depend on the vacuum condition during and after deposition.…”

Transport and optical gaps and energy band alignment at organic-inorganic interfaces

“…11,22 A sequence of As3d, Ga3d, and Sn4d photoelectron spectra acquired in real-time with a fixed incident photon energy of 105 eV is presented in Figure 2. These data formed part of a set of core and band edge spectra recorded during exposure of the S:GaAs(001) surface to a flux of SnPc, and part of a wider study of metal phthalocyanine growth on a range of substrates, including III-V semiconductors.…”

“…By selecting appropriate incident photon energies, both core and valence states are probed sequentially to provide parallel chemical and electronic information. This method has been applied to probe chemical and structural changes during the adsorption of monolayers (MLs), 9 inorganic films, 10 11 and here is applied to determine the energetics of semiconductor interfaces.…”