Carrier transport in layered semiconductor (p-GaSe)-ferroelectric (KNO3) composite nanostructures

The current-voltage characteristics and frequency dependences of the impedance of composite nanostructures fabricated on the basis of layered anisotropic semiconductor p-GaSe and ferroelectric KNO3 are studied. Multilayer nanostructures were obtained by introducing nanoscale pyramidal ferroelectric inclusions into a layered GaSe matrix. Hysteresis phenomena in current-voltage characteristics and abrupt changes in the conductance and capacitance in frequency dependences of the impedance are detected. These phenomena are associated with the collective effect of electric polarization switching in nanoscale 3D ferroelectric inclusions in the layered matrix, features of its local deformation, and polytype phase transitions in this matrix. X-ray, atomic-force microscopy, and impedance studies in a low (B < 400 mT) magnetic field show that the electrical characteristics of nanostructures are associated with the Maxwell-Wagner effect in nanostructures, the formation of quantum wells in GaSe during deformation of crystals in the region of nanoscale inclusion localization, and carrier tunneling in the structures.