Impedance and Photosensitivity Spectra of Nanocomposite Structures Based on Layered Semiconductor InSe and Ionic Salt RbNO₃

Abstract

Photoelectric properties of vertical ionotronic nanostructures based on layered semiconductor InSe and ionic salt RbNO3 are investigated. It is shown that the nanostructures consisting of 2D InSe layers, ultrathin layers of In2O3 oxide, and ionic salt ring‐shaped nanostructures, which are located in the (0001) planes of InSe crystal and periodically along its crystallographic C axis, have a high photosensitivity.

Charge Carrier Transport in Van Der Waals Semiconductor InSe Intercalated with RbNO3 Probed by Direct Current Methods

“…Photoconductivity spectra of InSe<RbNO 3 > investigated in earlier studies [18] revealed significant photosensitivity at hν < E g , which is higher than that in InSe single crystals. This was ascribed to the formation of a nanotextured interface between the ionic salt and layered crystal, as well as to the peculiarities of photoconductivity in anisotropic materials.…”

“…Atomic force microscopy (AFM) imaging of the vdW surfaces of InSe and GaSe crystals after insertion of ionotronic salts revealed the presence of nanodimensional 3D inclusions of ferroelectric phases. For the GaSe<RbNO 3 > structure, a pyramidal form was identified [17,20], whereas in the case of InSe<RbNO 3 >, small islands of ionic salt were observed which created nanosized rings with an outer diameter less than 50 nm [18]. Their height did not exceed the width of vdW gap (~3.5 Å) and the surface density in the plane (0001) ranged between 10 9 and 10 10 cm −2 .…”

“…For layered InSe and GaSe crystals, intercalates with ferroelectric salts (KNO 3 , KNO 2 , NaNO 2 , RbNO 3 , etc.) form a wide group of insertion compounds [17][18][19][20][21][22]. The insertion of the salts into the crystal structure was confirmed by X-ray studies.…”

“…Earlier ferroelectric nanocomposites obtained by exposing layered III-VI crystals to salt melts were investigated using AFM, X-ray photoelectron spectroscopy, optical absorption spectroscopy, etc. Although, the electrical properties of this hybrid semiconductor/ferroelectric system are interesting from both fundamental and practical points of view, so far they have only been studied by means of alternating current (a.c.) impedance spectroscopy methods [17,18]. In this paper, we report on the influence of ferroelectric rubidium nitrate (RbNO 3 ) intercalation on the electrical parameters of semiconducting n-type InSe vdW crystals and their anisotropy probed with direct current (d.c.) techniques.…”