## 1 Introduction  
In recent years, the diverse family of layered van der Waals (vdW) crystals has been attracting a great deal of attention as a versatile material platform for fundamental and applied research [1, 2, 3]. The rapid development in this field has renewed interest in intercalation, which is a powerful approach to engineer the properties of layered materials [4, 5]. The peculiarities of the crystalline structure of layered vdW crystals--namely, the absence of dangling bonds within a separate layer and large interlayer gaps (3-4 A)--enable the properties of pristine crystals to be tailored by means of intercalation (i.e., by the insertion of various guest species between layers). In particular, intercalation could be used as an effective method to introduce new functionalities or enhance the existing parameters of a promising class of semiconducting vdW crystals known as metal monochalcogenides, such as InSe, GaSe, etc. In the pristine form, these crystals have recently emerged as an excellent material base not only for quantum science, but also for a wide range of innovative technologies, including quantum metrology, high broadband photosensors, light-emitting diodes, resonant tunnelling transistors with multiple regions of negative differential conductance, and field-effect transistors (FETs) with high electron mobility exceeding that of silicon-based FETs [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]. For layered InSe and GaSe crystals, intercalates with ferroelectric salts (KNO3, KNO2, NaNO2, RbNO3, 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. In particular, the X-ray diffraction patterns of the InSe<RbNO3> structure indicate the presence of InSeand RbNO\({}_{3}\) phases and demonstrate the increase of the lattice parameter \(c\) (along the crystallographic C axis) to 29.641 A (for pristine InSe \(c=\) 24.946 A), while the in-plane lattice parameter \(a\) remains unchanged [19]. Atomic force microscopy (AFM) imaging of the vdW surfaces of InSe and GaSe crystals after insertion of iontornic 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 (\(\sim\)3.5 A) and the surface density in the plane (0001) ranged between 10\({}^{9}\) and 10\({}^{10}\) cm\({}^{-2}\). Photoconductivity spectra of InSe\(<\)RbNO\({}_{3}\)\(>\) investigated in earlier studies [18] revealed significant photosensitivity at \(h\
u<E_{\rm g}\), 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. The intercalation insertion of ferroelectric molecules into the interlayer space of III-VI semiconductors enables new mechanisms of charge accumulation, which is promising for the development of solid-state supercapacitors [17]. Thus, ferroelectric intercalating agents are promising materials for a wide range of applications, but little is known about their properties. 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].