A newly investigated approach for the control of tunnel resistance of nanogaps using field-emission-induced electromigration

Structural tuning of nanogaps using field-emission-induced electromigration with bipolar biasing

“…3(b), the tunnel resistance R of the nanogap also successfully decreases from over 100 TΩ to 48 kΩ by performing the activation using a current source with alternately reversing polarities. In our previous work, the tunnel resistance R in the current-source-based activation was reduced from over 100 TΩ to 70 MΩ with the increase of the preset current I S from 1 nA to 3.5 μA [15]. In this case, the tunnel resistance R of the nanogap obtained by the alternately biased activation was finally decreased to 48 kΩ, which is in the order of 1000 times lower than that of the current-sourcebased activation [15].…”

“…Recently, Araidai et al have found using first-principles calculations based on the densityfunctional theory (DFT) that surface atom under field emission (FE) evaporates with lower fields than the typical strength of field evaporation without FE. Then, FE-assisted surface atoms evaporate in the same direction as the electron flow [13], which is in good agreement with the direction of moving atoms controlled by the "activation" [11,12,[14][15][16].…”

“…In addition, one can facilely obtain the planar-type ferromagnetic nanogaps with Ni/Vacuum/Ni tunnel junctions using the activation with a voltage source [14]. Furthermore, we have also investigated the successful control of the nanogaps by directly adjusting the field emission current with a current source [15]. In this paper, we study a new approach for the fabrication of nanogaps using EM method induced by a field emission current with alternately reversing polarities.…”

“…In the activation scheme, when the field emission current flows from drain to source electrode, Ni atoms at the tip of the source electrode are activated and then are migrated from source to drain electrode [11,12,[14][15][16]. Recently, Araidai et al have found using first-principles calculations based on the densityfunctional theory (DFT) that surface atom under field emission (FE) evaporates with lower fields than the typical strength of field evaporation without FE.…”

“…In order to fabricate nanogaps more simply with wellcontrolled tunnel resistance, we have already investigated a novel technique for the formation of nanogaps using EM method induced by a field emission current (so-called "activation"), based on the phenomenon of moving atoms induced by a Fowler-Nordheim (F-N) field emission current flowing through the nanogaps [11,12,[14][15][16]. In the activation scheme, when the field emission current flows from drain to source electrode, Ni atoms at the tip of the source electrode are activated and then are migrated from source to drain electrode [11,12,[14][15][16].…”