Effects of Size Reduction on the Electrical Transport Properties of 3D Bi Nanowire Networks

Abstract

3D nanowire networks are fascinating systems for future microelectronic devices. They can be handled like macroscopic objects, while exhibiting properties of nanoscale materials. Here, the fabrication of free‐standing 3D bismuth nanowire networks with well‐controlled and systematically adjusted wire diameter and interconnectivity is presented. The samples are fabricated by pulse electroplating of bismuth into the pores of ion track‐etched membranes using an aqueous electrolyte. By optimizing the growth parameters, homogeneously grown, mechanically self‐supporting and free‐standing networks without a supporting matrix are achieved. Cross‐plane Seebeck coefficient and electrical resistance values are investigated as a function of nanowire diameter and temperature. The unique characteristics of these highly interconnected and mechanically self‐supported Bi 3D nanowire networks offer exciting perspectives for their implementation in, e.g., infrared detection based on thermoelectric effects, sensing, and THz applications.

3D Bi2Te3 Interconnected Nanowire Networks to Increase Thermoelectric Efficiency

“…The in-plane electrical conductivity measurements were performed in a four-probe system based on a Van der Pauw configuration (a commercial HMS-5500 Hall Effect Measurement system from Ecopia). Moreover, the Seebeck coefficient measurements of the out-of-plane configuration were also performed in a lab-made system consisting of two blocks of copper between which the sample was sandwiched, similar to those reported in ref ( 11 ). Then, the temperature of one of the copper blocks could vary around room temperature and the voltage on both sides of the sample was measured.…”

Polycrystalline bismuth nanowire networks for flexible longitudinal and transverse thermoelectrics

“…Bi ECD followed a slightly modified protocol as described elsewhere. 24,37,38 In brief, the electrochemical process was carried out in an aqueous electrolyte containing: 1 M HCl (hydrochloric acid fuming, 37%), 0.1 M BiCl 3 (bismuth chloride), 0.3 M C 4 H 6 O 6 (tartaric acid), 1 M NaCl (sodium chloride) and 1 M C 3 H 8 O 3 (glycerol). Bi was grown in the crossed nanopores of the PC templates via pulsed chronoamperometry, by applying to the working electrode (the metal-coated PC templates) a sequence of short voltage pulses versus a silver/silver chloride (Ag/AgCl) reference electrode ( potassium chloride -KCl saturated, E = 0.197 V against normal hydrogen electrode -NHE) from a PAR 263A Potentiostat/Galvanostat, while a platinum (Pt) strip was immersed in the bath to act as the counter electrode.…”

“…2,8,9 Although the study of the dependence of thermoelectric power on the diameter of individual Bi NWs and parallel NW arrays has been the subject of several previous studies, the experimental results are very contrasted, not allowing the identification of a clear trend. 1,5,6,[10][11][12][13][14][15][16][17][18] Several factors are likely to be at the origin of the puzzling results obtained on Bi NW arrays. Firstly, most measurements have been made on single crystal Bi NWs, some of which display different crystal orientations.…”

“…The temperature and diameter evolutions of the thermopower of electrodeposited Bi CNWs have been recently reported by applying out-of-plane thermal gradients. 24 Interestingly, unlike parallel arrays of NWs where thermal and electric current can only be applied in the direction parallel to the axis of the NWs, the 3D NW structure also allows measurements to be made in the macroscopic direction of the film plane, taking advantage of the excellent electrical connectivity. 19,21 On the other hand, interest in the development of transverse energy conversion devices has recently received a boost due to the emergence of new classes of materials and new transport phenomena in transverse geometry.…”

Cu Nanowire Networks with Well-Defined Geometrical Parameters for Catalytic Electrochemical CO2 Reduction

“…A previous study has clearly shown that such Pt nanowire networks have a higher stability than the commercial Pt/C catalysts for methanol oxidation. 37 Further examples include Bi nanowire networks for thermoelectrics 38 and Cu 2 O and ZnO nanowire networks for photoelectrochemical applications. 39,40 In this work, we exploit the structural advantages of 3D interconnected Cu nanowire networks with well-defined geometrical parameters and large electrochemically active surface areas.…”