Experimental Studies on the Dynamic Memcapacitance Modulation of the ReO3@ReS2 Composite Material-Based Diode

Abstract

In this study, both memcapacitive and memristive characteristics in the composite material based on the rhenium disulfide (ReS2) rich in rhenium (VI) oxide (ReO3) surface overlayer (ReO3@ReS2) and in the indium tin oxide (ITO)/ReO3@ReS2/aluminum (Al) device configuration is presented. Comprehensive experimental analysis of the ReO3@ReS2 material properties’ dependence on the memcapacitor electrical characteristics was carried out by standard as well as frequency-dependent current–voltage, capacitance–voltage, and conductance–voltage studies. Furthermore, determination of the charge carrier conduction model, charge carrier mobility, density of the trap states, density of the available charge carrier, free-carrier concentration, effective density of states in the conduction band, activation energy of the carrier transport, as well as ion hopping was successfully conducted for the ReO3@ReS2 based on the experimental data. The ITO/ReO3@ReS2/Al charge carrier conduction was found to rely on the mixed electronic–ionic processes, involving electrochemical metallization and lattice oxygen atoms migration in response to the externally modulated electric field strength. The chemical potential generated by the electronic–ionic ITO/ReO3@ReS2/Al resistive memory cell non-equlibrium processes leads to the occurrence of the nanobattery effect. This finding supports the possibility of a nonvolatile memory cell with a new operation principle based on the potential read function.

Optimization of the multi-mem response of topotactic redox La$_{1/2}$Sr$_{1/2}$Mn$_{1/2}$Co$_{1/2}$O$_{3-x}$

“…The existence of a large memcapacitive effect is confirmed by measuring the remanent -overall-device capacitance C REM after the application of voltage write pulses between 0 and 1 V (small enough to avoid triggering a RESET transition). These measurements are shown in Figure 3(e) and display a C HIGH /C LOW ratio of ≈ 100, that is an order of magnitude higher than the figures reported so far [25][26][27][28][29][30][31][32][33]. We notice that C REM is a function of the equivalent circuit elements (Table 1) and the frequency ω, as described by the Maxwell-Wagner model [36].…”

“…A very interesting topotactic redox perovskite is La 1/2 Sr 1/2 Mn 1/2 Co 1/2 O 3−x (LSMCO), which displays and oxidized -more conducting-phase with x = 0 and a rhomboedral R 3c structure, as well as a reduced -more resistive-phase with x =0.62 and an orthorombic Pbnm structure [23]. We have shown [24] that epitaxial Nb:SrTiO 3 /LSMCO structures display a robust memristive behavior concomitant with a memcapacitive effect -reversible change in the capacitance between different non-volatile states [25][26][27][28][29][30][31][32][33]-. The memcapacitance found in this system -C HIGH /C LOW ≈ 900 at 10 kHz and ≈ 100 at 150 kHz-was the highest reported to date by a factor of ≈ 10 and originates at the NSTO/LSMCO interface, where a switchable p-n diode is formed [24].…”