FEATURES OF PLASMON-STIMULATED SILVER PHOTODOPING OF THIN As10Ge30S60 LAYERS

The paper presents the results of studies of photostimulated diffusion of silver, enhanced by the surface plasmon-polariton (SPP) field, into thin films of As10Ge30S60 chalcogenide glass (ChG). To ensure the excitation of the SPP at the interface between Ag and ChG, substrates in the form of diffraction gratings with a period of 519 nm and a relief depth of 21 nm, formed on films of chalcogenide photoresist by the method of interference lithography, were used. An 85 nm thick Al layer, an opaque silver layer 80 nm thick and an As10Ge30S60 layer 13 nm thick were successively deposited onto these substrates using thermal deposition in a vacuum. The samples were irradiated with p-polarized He-Ne laser radiation (λ = 632.8 nm). The radiation of the same laser, attenuated by two orders of magnitude, was used to record the SPP resonance in the angular dependence of the specular reflection, which made it possible to study the kinetics of photostimulated processes in the Ag-As10Ge30S60 thin-layer structure. In particular, the kinetics of growth in the effective refractive index of the As10Ge30S60 layer as a result of photodoping with silver, the concentration of photodissolved silver, and the coefficients of photostimulated diffusion of silver in ChG were determined for exposure with SPP excitation and with and without plasmon-polariton excitation. It has been established that the excitation of SPP at the Ag/As10Ge30S60 interface during exposure leads to a threefold increase in the photostimulated flux of silver ions. A possible mechanism has been proposed to explain the acceleration of photostimulated metal diffusion in the structure under study due to the excitation of SPP: an increase in the intensity of generation of electron-hole pairs in the As10Ge30S60 layer under the influence of the plasmon field and/or plasmon-stimulated internal photoemission of electrons from the metal into the As10Ge30S60 layer with subsequent drift of silver ions into the chalcogenide under the influence of an additional electric field.