Formation of Graphite Nanostructures on the Surface of Layered n-InSe Crystal

The possibility of the formation of graphite nanostructures on the (0001) surface of layered InSe semiconductor by the sputtering in vacuum is shown. The InSe single crystals were grown by the Bridgman method from a nonstoichiometric melts In1.03Se0.97 in silica ampoules. They had the crystalline structure of the γ-polytype, n-type conductivity, and an electron concentration of 1015 cm–3 at room temperature. The substrates for carbon deposition with dimensions of 4(4(0.2 mm were prepared by mechanical exfoliation along the InSe layers. The deposition of the material was carried out at substrate temperatures in the range of 300-400 °C and upon irradiation of the growth zone with high-energy ultraviolet light. The latter was generated by halogen lamps with a quartz shell. In addition, a constant electric voltage was applied to the substrate to improve the formation of critical nuclei of carbon nanostructures. The carbon was sputtered from an electrode, which was under positive voltage of 2800 V in a vacuum of 10 – 4 Pa during 50 min. The obtained structures are long nanoformations with length about several micrometers. Their location is determined by the dislocation grid of the InSe surface. The height of the carbon nanostructures does not exceed 100 nm. This ensures their transparency in a wide spectral range. In addition, such nanostructures have high electrical conductivity, small refractive index (~ 1.5) in the spectral sensitivity range of InSe, and a heterojunction can be formed at the graphite/n-InSe interface. Grown carbon nanostructures contribute to the propagation of incident light into the depth of crystal. The characteristic peaks of (-InSe crystals and graphite are observed in the Raman spectrum. They indicate the absence of chemical interaction between the deposited material and the substrate, some plastic deformation of the substrate and the presence of a large number of structural defects in the carbon nanoformations.