Memory diodes with nonzero crossing

Abstract

Memristors combine switching, memory, and rectification functions in two-terminal nanoelectronic devices. The theory says that their current-voltage (I-V) characteristics cross over at the zero crossing point (I = V = 0), and the results reported hitherto conform to this theorem. Here, we extend the family of memristive devices, adding memory diodes (memdiodes) comprising SrTiO3 pn junctions that display unique combination of rectification, hysteresis, and nonzero crossing. Reverse bias polarization gives rise to a nonzero open circuit voltage that persists after the junction is disconnected from the external circuit. This opens up an opportunity for a new type of nonvolatile memories.

Parallel Band and Hopping Electron Transport in SrTiO3

“…Reproduced with permission. [ 6 ] Copyright 2013, American Institute of Physics. [22] Work function of the left contact ϕ M …”

“…Although the I -V curves in Figure 1 were measured through a junction between a Fe:STO fi lm and a Nb:STO substrate, [ 6 ] the latter is modeled here as a metallic Schottky contact due to the high donor concentration in Nb:STO. The work function of this contact was found by fi tting the steady-state I -V curve in Figure 1 (black squares) with model calculations as described below, yielding a value of 4.3 eV (see Table 1 ).…”

“…The thickness of this layer in our modeled structure was found to be 140 nm, similar to the nominal thickness of the Fe:STO layer in the device itself (≈160 nm). [ 6 ] On the other side of the Fe:STO layer another metallic Schottky contact is modeled, with a work function of 5.6 eV (see Table 1 ). Similarly to the other contact, this value was obtained by fi tting the steady-state I -V curve in Figure 1 to model calculations.…”

“…Consequently, STO-based electronic devices such as bipolar transistors, [ 3 ] Schottky diodes, [ 4 ] memristors, [ 5 ] and p-n junctions [ 6 ] were reported recently. In the latter work, unusual current-voltage ( I -V ) characteristics were observed in cyclic voltammetry scans of a heteroepitaxial structure comprising a thin (≈160 nm) fi lm of 0.1 site% Fe-doped SrTiO 3 (Fe:STO) on a 1.4 site% Nb-doped SrTiO 3 (Nb:STO) (001) single-crystal substrate.…”

A nonvolatile memory device with very low power consumption based on the switching of a standard electrode potential

“…Metal/oxide/metal resistive switching devices are reported to show a voltage-switching behavior originating from electrochemical reactions in the device. [12][13][14] Such voltage switching is observed both in filament- 12,13 and interface-type 12,14 resistive switching devices. For the filament-type device, previous reports showed instability in performance.…”