**5. Formation of microrelief structures on the surface of chalcogenide films**

One of the most promising uses of optical and electron beam recording on CVS is a direct one-step process of microrelief formation on the surface of films, which is

## *Recording of Micro/Nanosized Elements on Thin Films of Glassy Chalcogenide Semiconductors… DOI: http://dx.doi.org/10.5772/intechopen.102886*

closely related to induced mass transfer (vertical or lateral directions) in amorphous material under illumination [4, 36–39]. The formation of relief on the surface of ChS films is possible by a purely optical method due to photoinduced mass transfer (FM) under the action of the light from the spectral region of the absorption edge even at relatively low intensities of the light wave. However, due to light diffraction, the lateral scale of such topographic structures is limited, which blocks the formation of nanoscale information elements [3]. In direct one-stage laser or electron-beam recording, there is an irreversible amplitude-phase optical and geometric structuring of the surface. This effect can be used for the manufacture of microlenses, amplitude-phase optical elements. The process of direct photoinduced fabrication of microrelief structures on CVS films by lateral mass transfer was studied on films of different compositions and with different irradiation methods. As a result, the observed process models were proposed and areas of possible application were identified [4, 36–38]. The possibility of creating planar diffraction optical elements during electron-beam exposure with a local change in the refractive index was experimentally demonstrated. The lens is created in the form of electron beam-recorded annular zones with a stepwise decrease in refractive index. The image of the Fresnel lens obtained by this method is shown in **Figure 7**. The minimum width of the elements in the recorded image is ~0.6–1.0 μm [31, 39].

Direct single-stage laser or electron beam recording is more efficient in nanosized layered structures Se/As2S3 and Sb/As2S3 than in homogeneous layers of As2S3 [6, 39]. The effect of photoinduced mass transfer allows to obtain holographic gratings, integral optical elements by a purely optical method at relatively low intensities of light fluxes [4, 13, 38, 39]. The image of the diffraction grating obtained by the direct (optical) method due to photoinduced mass transfer of the substance of the CVS film is shown in **Figure 8**.

The relief shape and diffraction efficiency can be changed by the ratio of the polarization of the recording rays and the beam of additional illumination.

The photoinduced changes in amorphous Ge-based chalcogenide layers deposited on gold nanoparticles change significantly. The rate and final magnitude of the volume change is higher in a structure with localized plasmon fields, mainly because the latter affects the processes of charge generation and the movement of atoms, initiated by illumination. The results showed that the superposition of the localized plasmon field of nanoparticles with the electromagnetic field of incident photons during irradiation enhance light-induced transformations (**Figure 9**) [32].

#### **Figure 7.**

*Image of a Fresnel lens obtained by the method of direct one-stage process forming microrelief (a), e-beam fabricated scattering lens on Se/As2S3 NML and its profile measured by AFM (b) [6].*

*AFM image of diffraction gratings recorded at temperatures of 77 K (a) and 300 K (b) on As20Se80 thin films [38].*

#### **Figure 9.**

*AFM surface morphology of the holographic grating recorded in the pure chalcogenide layer (a) and in the sample with GNPs (b), and the cross-section of the created surface structures (c): 1—pure chalcogenide layer, 2—sample with GNP [32].*

*Recording of Micro/Nanosized Elements on Thin Films of Glassy Chalcogenide Semiconductors… DOI: http://dx.doi.org/10.5772/intechopen.102886*

The use of a layer of gold nanoparticles allows a higher level of mass transfer and more efficient modification of the surface of a chalcogenide semiconductor film to be realized.
