Light-induced mass transport in amorphous chalcogenides: Toward surface plasmon-assisted nanolithography and near-field nanoimaging

Abstract

Two types of amorphous functional materials, based on light‐sensitive inorganic compounds like Se and As20Se80 chalcogenide glass (ChG) were investigated with the aim to establish the influence of plasmonic fields, excited by the recording light in nanocomposite layers made of these compounds and gold nanoparticles on their photomechanical response. Both these basic materials are characterized by pronounced photoplastic effect and used for real‐time optical recording of optoelectronic elements (based mainly on surface relief gratings) due to high photofluidity and polarization‐dependent mass‐transport. We have established that mass‐transport processes in these ChG can be enhanced in the presence of localized plasmonic fields generated by light if the condition of surface plasmon resonance (SPR) is fulfilled. The subjects of special interest are the mass‐transport processes at nano‐scale stimulated in the nano‐composite layers either by uniform or periodically distributed optical fields. It was found that irradiation by light in the presence of SPR really enhanced the efficiency of mass‐transport and produced surface nanostructurizations. The variation in the topography follows closely and permanently the underlying near field intensity pattern. Nanostructurization of photosensitive amorphous As20Se80 film by surface plasmon near field irradiation.

Low-temperature photo-induced mass transfer in thin As20Se80 amorphous films

“…Our theoretical analysis is based on alternative driving force (in line with predictions and previous results [22,23]), namely, steady state lateral electric field, which appears in ACFs under non-homogeneous illumination by band gap light (Dember field [24])…”

“…To satisfy the neutrality condition, one can suppose p n  . It is worth noting that existence of lateral steady state electric field under inhomogeneous illumination of As 20 Se 80 film was recently demonstrated [23] using Kelvin probe force microscopy technique.…”

Formation of Nanoscale Structures on Chalcogenide Films

“…This technical construction is usually called the scattering Super‐RENS‐type one . The technology of excitation of metallic nanoparticles and the application of the optical near‐field emission to the exposure of the photosensitive layers is revealed to be quite efficient for the formation of nano‐sized structures . The reading of recorded nano‐sized imprints can be executed by near‐field probes …”

“…One of the ways to overcome the diffraction limit can be the use of a near light field of nanoparticles (NPs) of metals integrated within a thin film of CVS, that is, the formation of peculiar plasmon nanostructures . The generation of localized plasmons in NPs of noble metals is widely used to enhance the interaction of light with a matrix surrounding those plasmon nanostructures.…”

“…As is known, the generation of electron‐hole pairs at the excitation of the energy gap is a general component of the mechanism of the processes of mass transport in chalcogenide films . A local increase in the electric field causes a significant enhancement of the mass transport effectiveness of the substance of a film on the nanoscale . Due to the interference of the light field of such plasmons and to a change in the wavelength or polarization of the incident light, the significantly more complicated reliefs of a surface, than those obtained with the help of the ordinary interference lithography, can be created.…”