Growth of fiberform nanostructures on metal surfaces by helium plasma irradiation

Abstract

Helium plasma irradiation to various metals leads to peculiar morphology changes as forming fiberform nanostructures called fuzz when a certain set of conditions is satisfied. In this Tutorial, we overview experimental observations about the fuzz growth process, conditions, growth rate, etc. on tungsten (W), and fuzz growth observed on other various metals. The fuzz growth mechanism, open questions about fuzz growth, and current understandings on these issues are discussed based on simulation and theoretical works. Several applications (gas sensors and photocatalytic application) with fuzz are shown. We hope that this Tutorial will help new researchers in this field to perform experiments and simulations to reveal new perspectives of fuzz.

Growth origin of large-scale fiberform nanostructures in He–W co-deposition environment

“…In addition, fiberform nanomaterials have various practical applications including optical applications 17 , 18 . The practical application of fuzz as photoelectrode and gas sensor has been explored so far 6 . Improved performance of gas sensor for hydrogen gas detection has been demonstrated on oxidized W fuzz 19 .…”

“…Therefore, understanding the interaction between He and W is important and has been studied intensively. Helium plasma irradiation on a W surface forms fiberform nanostructures called fuzz 3,4 when the temperature and incident ion energies are in the range of 1000-2000 K and above 20-30 eV, respectively 5,6 . The necessary condition for fuzz growth could be satisfied around the strike point in the ITER divertor 7 .…”

Growth origin of large-scale fiberform nanostructures in He-W co-deposition environment

“…Therefore, understanding the interaction between He and W is important and has been studied intensively. Helium plasma irradiation on W surface forms fiberform nanostructures called fuzz 3,4 when the temperature and incident ion energies are in the range of 1000-2000 K and above 20-30 eV, respectively 5,6 . The necessary condition for fuzz growth could be satisfied around the strike point in the ITER divertor 7 .…”

Increased Photoelectrochemical Performance of Vanadium Oxide Thin Film by Helium Plasma Treatment with Auxiliary Molybdenum Deposition

“…[7,8] Various processing methods have been used to fabricate vanadium oxide thin films and nanostructures. For example, pulsed laser deposition (PLD), [9] magnetron sputtering, [10] chemical vapor deposition (CVD), [11] plasma-enhanced CVD, [12] solgel method, [13,14] and sol-gel dip coating [15] were used to deposit thin films; hydrothermal process, [16] thermal pyrolysis, [17] electrospinning, [18] ion beam sputtering, [19] and helium (He) plasma treatment [5] were used for nanostructuring.Among these methods, He plasma treatment is a novel method, which forms fiberform nanostructures (FNs) called fuzz on various metals including tungsten, molybdenum, rhenium, rhodium, tantalum, platinum, niobium, and V. [5,[20][21][22][23][24][25] The process is a bottom-up process accompanied by the growth of He bubbles on the top surface layer (thickness of 100-200 nm) and the formation and diffusion of adatoms. [26][27][28][29][30] Application of oxidized fuzz has been studied including the application of tungsten trioxides (WO 3 ) as gas sensors [31][32][33][34][35][36] WO 3 , iron oxides, [37,38] titania, [39,40] and V oxides [5] as photoelectrodes.…”

“…Among these methods, He plasma treatment is a novel method, which forms fiberform nanostructures (FNs) called fuzz on various metals including tungsten, molybdenum, rhenium, rhodium, tantalum, platinum, niobium, and V. [5,[20][21][22][23][24][25] The process is a bottom-up process accompanied by the growth of He bubbles on the top surface layer (thickness of 100-200 nm) and the formation and diffusion of adatoms. [26][27][28][29][30] Application of oxidized fuzz has been studied including the application of tungsten trioxides (WO 3 ) as gas sensors [31][32][33][34][35][36] WO 3 , iron oxides, [37,38] titania, [39,40] and V oxides [5] as photoelectrodes.…”