The role of Joule heating in the formation of nanogaps by electromigration

Abstract

Link to publication in University of Groningen/UMCG research database Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. We investigate the formation of nanogaps in gold wires due to electromigration. We show that the breaking process will not start until a local temperature of typically 400 K is reached by Joule heating. This value is rather independent of the temperature of the sample environment ͑4.2-295 K͒. Furthermore, we demonstrate that the breaking dynamics can be controlled by minimizing the total series resistance of the system. In this way, the local temperature rise just before breakdown is limited and melting effects are prevented. Hence, electrodes with gaps Ͻ2 nm are easily made, without the need of active feedback. For optimized samples, we observe quantized conductance steps prior to the gap formation.

Real-Time TEM Imaging of the Formation of Crystalline Nanoscale Gaps

“…In the initial bowtie geometry [ Fig. 3(a)] the localized Joule heating within the narrow bridge causes an increased local temperature, which we estimate to be approximately 530 K (in rough agreement with other estimates [4,24,27]). The temperature rise of the bridge leads to increased gold mobility in that region, and a greater concentration of thermally excited adatoms and vacancies.…”

“…We find that welldefined crystal facets appear as the nanogap forms. This is clear evidence that the nanogap does not melt during FCE, in contrast to what can occur during the single voltage ramp procedure [4,5]. We explain the appearance of crystal facets during FCE by an ''unzipping'' model where electromigration occurs layer by layer, due to preferential thermal excitation of gold atoms that lie on exposed, high-mobility crystal planes of the lattice.…”

“…One must form highly ordered nanoscale gaps [1] that provide a reproducible environment for the molecule and allow for efficient electrostatic coupling to nearby gate electrodes. Electromigrated nanogaps formed with a single voltage ramp [2] have been suggested for constructing singlemolecule electronics, but the thermal runaway [3], melting [4,5], and stochastic break [2] characteristic of this process do not provide the required reproducibility.…”

Self-breaking in planar few-atom Au constrictions for nanometer-spaced electrodes

“…Contact to the bridge is made by large wires which contribute a small series resistance. 5 The resistance between bonding pads before the wires are narrowed is typically 100-200 ⍀. To initially narrow the gold wires by electromigration, we use an active breaking scheme, 6 similar to the ones previously reported.…”

Healing Effect of Controlled Anti‐Electromigration on Conventional and High‐Tc Superconducting Nanowires

“…Examples illustrating the benefits of controlling the EM process include the creation of few nanometer gaps between two Au pads [8][9][10][11][12] with the aim to electrically address single molecules [13][14][15] , the electrical sculping of nanowires to obtain atomic point contacts [16][17][18] , metal purification and separation of atoms in binary alloys due to the mass selectivity of the process 19 , current-induced crystallization 20 , and cleaning of graphene layers 21 .…”