X-ray Scanning Photoelectron Microscopy Research Articles

Morphology and composition of nanoinclusions in (Fe, Ni)0.25TiSe2

A nanocomposite material consisting of (Fe,Ni)4Se5 and Ti3Se4 nanocrystals coherently bounded with the (Fe,Ni)0.25TiSe2 substrate was obtained during the synthesis of the (Fe, Ni)xTiSe2 bi-intercalation compound from the mixture of Fe0.25TiSe2 and Ni0.25TiSe2. The morphology of these composite crystals has been studied using optical, scanning electron and atomic force microscopy. The electronic structure of the inclusions was studied using X-ray scanning photoelectron microscopy (SPEM). We have shown that (Fe,Ni)4Se5 and Ti3Se4 inclusions grow simultaneously with (Fe,Ni)xTiSe2 substrate crystal on its (001) plane. The lateral growth of the (Fe,Ni)xTiSe2 crystal is accompanied by the “capturing” of the (Fe,Ni)4Se5 and Ti3Se4 inclusions by the (Fe,Ni)0.25TiSe2 substrate resulting in the formation of the composite crystal.

Spectromicroscopic investigation of polymer light-emitting device degradation

The degradation mechanism of a polymer light-emitting device (PLED) based on poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) (PEDOT:PSS) was investigated by X-ray scanning photoelectron microscopy. Spectromicroscopic analysis of the surface of the emission layer (EML) of the degraded PLED revealed that island-like structures, containing sulfur (S) presumably in sulfide (–C–S–C–) and thiol (–C–S–H) configurations, were generated. The analysis results further suggest that S out-diffused from the PEDOT:PSS layer and formed sulfide and thiol configurations in the EML, and that effective conduction path channels were generated through the island-like structures for current dissipation between the electrodes, resulting in PLED degradation.

Imaging of patterned self-assembled monolayers by scanning photoelectron microscopy

We have applied soft X-ray scanning photoelectron microscopy (SPEM) to image and characterize molecular patterns produced by electron irradiation of various aliphatic and aromatic thiol-derived self-assembled monolayers (SAMs) through masks. The fabricated patterns can be clearly distinguished and the inverse contrasts for the Au 4f and C 1s images suggest that the goal of chemical imaging has been achieved. The thickness of the films in the irradiated areas appeared to be higher than that in the non-irradiated ones. This can be explained by the adsorption of airborne carbon-containing molecules on the irradiated areas. In addition, the N 1s images were acquired from the structured films of NO 2 (C 6 H 4 ) 2 SH on gold to monitor the electron irradiation-induced transformation of the nitro tail groups into amino moieties. However, no chemical contrast related to the nitro-amino transformation was observed. This can be explained by the small intensity of the nitrogen photoelectron emission with respect to the inelastic background originated from the substrate and by the X-ray induced modification of the lithographic pattern during the image acquisition. The modification of aromatic SAMs caused by the zone-plate-focused X-ray beam has been utilized for direct lithographic writing by the microprobe.