**4. The use of nanocomposite photosensitive materials, the formation of images on which is carried out using the methods of nanoplasmonics**

Plasmonic nanolithography, which uses surface plasmons to create submicron elements, is a promising technology for producing nanoscale structures. Plasmonics can focus light into zones smaller than the diffraction limit, due to the connection of light with the surface collective vibrations of free electrons at the metal-dielectric interface. Surface plasmon resonances (SPP) have been used to create nanoscale structures [27]. The method of plasmon nanolithography is being developed in which metal lattice masks are used to excite SPP and structural nanoscale elements. The mask is in close contact with the photoresist applied to the substrate. Typically, the incident light passes through the mask through the SPP and is directed to the photoresist [27]. It was demonstrated that the use of surface plasmons in the optical near field of a metallic mask can produce fine patterns with a subwavelength resolution. Using a silver grating mask with 300 nm periodicity, lithography with 100 nm pitch has been demonstrated by using the interference of surface plasmon waves within the grating area [28].

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

The method of plasmon nanolithography was used for the alternative design of the Super-RENS recording method. In this method, a layer of noble metal oxides (AgOx, PtOx, and PdOx) was used instead of the Sb layer. Using surface plasmons has greater possibilities for the creation of super-dense recording systems. Irradiation of the oxide layer led to the decomposition of the oxide and the formation of a layer of metal nanoparticles. The process of chemical decomposition occurs in the temperature range from 400°C to ~500°C. Surface plasmons, excited by light on the formed nanoparticles of precious metals, generate optical near-field radiation, which is exposed to the photosensitive layer. The structure of such a medium is shown in **Figure 5** [26]. The media with the Ag2O layer were studied in the most detail. The Ag2O layer in the Super-RENS carrier acts as a center of strong light scattering in the local region of the multilayer carrier. The optical near field, which is created around the scattering center with Ag2O, is 40 times stronger than the field created by the antimony layer [29, 30]. Studies have shown that the higher efficiency of high-resolution super-RENS disks with an AgOx layer is associated with the formation of localized surface plasmons by silver clusters dissociated from the AgOx layer. The diameter of the silver nanoparticles was approximately 4 nm. The density and distribution of dissociated silver nanoparticles are affected by the intensity of focused laser radiation. Localized surface plasmons improve the reading efficiency in such media [31].

One of the possible ways to overcome the diffraction barrier can be the use of the near light field of metal nanoparticles (NPs) integrated into chalcogenide films, i.e., the formation of a kind of plasmonic nanostructures [5]. This field arises upon irradiation with light with a certain wavelength due to the excitation of collective oscillations of free electrons in NPs (surface plasmon resonance (SPR)). The spatial distribution of this field can be changed in a controlled manner due to appropriate changes in the size and geometry of the woofer. The technology of excitation of metal nanoparticles and the use of optical near-field radiation for the exposure of photosensitive layers has proved to be quite effective and continues to develop in the creation of new types of media for recording nanoscale structures. A schematic representation of the information carrier with a layer of nanoparticles of precious metals is shown in **Figure 6** [32].

Nanoparticles of precious metals with sizes of the order of tens of nanometers can have a significant impact on the processes of recording information in different types of optical and magnetic media. The technology of using nanoparticles is one of the ways to overcome the diffraction limit in the process of recording nano-sized structures. The generation of localized plasmons in noble metal nanoparticles is widely

#### **Figure 5.**

*The structure of the carrier made by technology super-RENS using oxides of noble metals [26].*

#### **Figure 6.**

*Information carrier with a layer of noble metal nanoparticles: (a) schematic diagram (cross-section) of the created structures with gold nanoparticles (GNPs) and chalcogenide layer; (b) SEM picture of the created GNPs [32].*

used to enhance the interaction of light with the matrix surrounding these plasmon nanostructures. The incident light, which is absorbed by the nanoparticles and transforms into collective oscillations of free electrons in them, leads to a strong amplification of the local electric field [31]. Metal nanoparticles effectively absorb light. Their ability to focus light in small volumes has led to the use of woofer in a variety of areas, including as light concentrators for the solar cells. The light-concentrating properties of metal nanostructures are a consequence of the amplification of electromagnetic fields due to the generation of localized plasmons [31, 33–35]. Light-induced plasmon heating of a magnetic medium in the process of magnetic recording (with a built-in plasmon antenna) can be used to implement the mode of thermal assistance and, ultimately, to increase the density of information recording [31, 33]. The surface plasmon interference nanolithography (SPIN) allows to obtained uniform interference patterns far beyond the free-space diffraction limit of the light. This technique provides a new alternative fabrication method for nanodevices [28].
