InSe/CrSe Interfaces Performed as Resistive Switches and Band Filters for Gigahertz/Terahertz Communication Technology Applications

Abstract

Herein chromium selenide (n-CrSe) nanosheets are deposited onto amorphous indium selenide (n-InSe) thin films by the thermal evaporation technique under a vacuum pressure of 10−5 mbar. The formed InSe/CrSe heterojunctions are structurally, optically and electrically investigated. InSe/CrSe heterojunctions exhibited a band structure discontinuities at the InSe/CrSe interfaces presented by a conduction and valence band offsets of 0.50 eV and 0.65 eV, respectively. The isotype InSe/CrSe heterojunctions exhibited resistive switching property under a forward and reverse biasing voltages of 1.5 V and 0.3 V, respectively. In addition computer assisted fittings which were carried out on the current–voltage characteristics of the InSe/CrSe devices have shown the existence of large barrier height of 1.75 eV at the InSe/CrSe interfaces. Moreover, low amplitude ac signal analyses have shown that the device under study performed as negative conductance sources with increased negative conductance values with increasing signal frequency. The negative conductance effect resulted from the deficiency of selenium atoms in InSe and CrSe as confirmed by the energy dispersive X-ray spectroscopy. Furthermore combination of the analysis of the picofarad level- capacitance with the conductance allowed determining the cutoff limits of the InSe/CrSe devices when treated as signal filters. The cutoff frequency of the InSe/ CrSe devices varied in the range of 10M-1.1 THz assuring the suitability of the devices for megahertz/gigahertz/terahertz technology applications