Humidity induced resistive switching and negative differential resistance in a-Fe2O3 porous thin films

Resistive switching (RS) phenomenon at a power level on the order of nW is observed in a porous alpha-Fe2O3 thin film. The samples are prepared on glass substrates using spin coating with a sol-gel solution of 141.5 mM Fe(III) acetylacetonate in acetone followed by annealing at 550 degrees C for 75 min in air. This process produces a semicontinuous alpha-Fe2O3 thin film. AC I-V curves were acquired in a humidity-controlled environment, where otherwise the I-V characteristics are linear. Sweeping the voltage of the device from 0 to 10 V at the rate of 0.2 V/ s with a triangular waveform, the device is in a low resistive state (LRS) from 0 to similar to 4 V, at which point the current sharply decreases from similar to 4-10 V, which is the signature of a negative differential resistance (NDR). Sweeping back from 10 to 0 V, the device remains in a high resistive state (HRS). The I-V curves are symmetric and highly reproducible, exhibiting the RS and NDR phenomena in the negative bias. A ratio of HRS/LRS > 12 at 2 V bias was achieved in both positive and negative bias regions. The RS and symmetric NDR behavior of the device is attributed to the trapping and de-trapping of the carriers at the space charge region formed by the movement of ions from water molecule dissociation towards respective electrode/material interface.

Automated summary

The resistive switching phenomenon at a power level of nW has been observed in a porous alpha-Fe2O3 thin film, which is attributed to the trapping and de-trapping of carriers at the space charge region formed by the movement of ions. The film is prepared under specific conditions and exhibits the phenomenon in a humidity-controlled environment.