Coexistence of resistance switching and negative differential resistance in the α-Fe₂O₃ nanorod film

Abstract

We report the coexistence of resistance switching (RS) behavior and the negative differential resistance (NDR) phenomenon in the α-Fe2O3 nanorod film grown in situ on a fluorine-doped tin oxide glass substrate. The reversible switching of the low- and high-resistance states (LRS and HRS, respectively) of the film device can be excited simply by applying bias voltage. The switching from the HRS to the LRS was initiated in the negative bias region, whereas the NDR process followed by the reversion of the HRS occurred in the positive bias region. With the increase in compliant current (CC), the carrier conduction models of the LRS and the HRS both changed and the current-voltage (I-V) relationships in the NDR region were seriously affected by the thermal process according to the level of applied CC. The co-existence of RS and NDR was possibly caused by defects during migration, such as oxygen vacancies and interstitial iron ions, which were formed in the α-Fe2O3 nanorod film. This work provided information on the ongoing effort toward developing novel electrical features of advanced transition metal oxide devices.

Metal Ions Redox Induced Repeatable Nonvolatile Resistive Switching Memory Behavior in Biomaterials

“…Furthermore, the NDR effect is perpetually present in the negative bias region of I−V curves, for our memory cells, most of the oxygen vacancies are easily accumulated at the interface of Ti/biofilm because of potentially Ti oxide and supply from reversible reaction of hydroxyl functional groups, which are the common component of biological materials. 29,46 This reaction process could be described by the following equation: 47…”

Non-equilibrium character of resistive switching and negative differential resistance in Ga-doped Cr2O3 system

“…Yang et al [19] observed resistive switching and NDR in Au/BTO/FTO system, where the behaviour was explained in terms of trapping and de-trapping electrons at the interfaces. The coexistence of RS and NDR in α-Fe 2 O 3 nanorods was attributed to defects states (oxygen vacancies and interstitial Fe ions) [11]. In our samples, the current (I) in the S1 segment (LRS) of P mode after reaching a peak value (I P ) at bias voltage V P started to decrease down to a valley, which is either levelled off or creeping up at higher voltage (V>V P ) depending on the limit of bias voltage.…”

“…1(g) shows that I-V curves in the low voltage regime of the S1 segment and entire S2 segment followed power law ( ~ ) with exponent m in the range 1.05-2.37 and 0.92-1.13, respectively. For trapping free SCLC mechanism in solid state devices, the exponent is 2; otherwise, exponent values can be less than 2 [11][12]30]. This means the I-V curve in the S2 segment does not follow a typical SCLC mechanism.…”

“…The Schottky equation and P-F equation were not applicable for NDR regime and above in the S1 segment of I-V curve. Although many metal oxides with M/MO/M structure have shown the coexistence of resistive switching and NDR effect [9,11,31], but the exact mechanism is not clear. Jia et al [20] observed the NDR in negative voltage side of I-V loop.…”

“…The thin films of transition metal oxides, e.g., Cr 2 O 3 [7], Ga 2 O 3 [8][9], Al 2 O 3 [10], Fe 2 O 3 [11], Ga-doped Fe 2 O 3 [12], Ba 0.7 Sr 0.3 TiO 3 [13], NiO [14], TiO 2 [15][16], and SiO 2 [17] have shown different types of resistive switching, i.e., unipolar, bipolar or abnormal nature.…”