Precursor sticking coefficient determination from indented deposits fabricated by electron beam induced deposition

• Alexander Kuprava and
• Michael Huth

Beilstein J. Nanotechnol. 2025, 16, 35–43, doi:10.3762/bjnano.16.4

• precursor parameters needed for this model. In this work we introduce such a method to derive the precursor sticking coefficient as one member of the precursor parameter set. The method is based on the analysis of the different growth regimes in FEBID, in particular the diffusion-enhanced growth regime in

• the center region of an intentionally defocused electron beam. We employ the method to determine the precursor sticking coefficient for bis(benzene)chromium, Cr(C6H6)2, and trimethyl(methylcyclopentadienyl)platinum(IV), Me3CpPtMe, and find a value of about 10−2 for both precursors, which is

• substantially smaller than the sticking coefficients previously assumed for Me3CpPtMe (1.0). Furthermore, depositions performed at different substrate temperatures indicate a temperature dependence of the sticking coefficient. Keywords: adsorption; continuum model; FEBID; nanofabrication; sticking coefficient

3D superconducting hollow nanowires with tailored diameters grown by focused He⁺ beam direct writing

• Rosa Córdoba,
• Alfonso Ibarra,
• Dominique Mailly,
• Isabel Guillamón,
• Hermann Suderow and
• José María De Teresa

Beilstein J. Nanotechnol. 2020, 11, 1198–1206, doi:10.3762/bjnano.11.104

• volume rapidly decreases as a function of the ion beam current for the same dose (Figure 2). When using high currents several effects can play a role in this dependence such as precursor depletion, local heating, which decreases the precursor molecule sticking coefficient, and low precursor diffusion

Effect of annealing treatments on CeO₂ grown on TiN and Si substrates by atomic layer deposition

• Silvia Vangelista,
• Rossella Piagge,
• Satu Ek and
• Alessio Lamperti

Beilstein J. Nanotechnol. 2018, 9, 890–899, doi:10.3762/bjnano.9.83

• the Ce(thd)4 molecules do not effectively diffuse onto the substrate surface and the surface coverage on the TiN or Si substrates remains strictly connected to the surface roughness, which is higher on the TiN surface (compared to Si). We should keep in mind that the sticking coefficient of Ce(thd)4

Modelling focused electron beam induced deposition beyond Langmuir adsorption

• Dédalo Sanz-Hernández and
• Amalio Fernández-Pacheco

Beilstein J. Nanotechnol. 2017, 8, 2151–2161, doi:10.3762/bjnano.8.214

• fractional molecule coverage θ = N/N0 is given by [25]: The first, second and third terms on the right hand side of Equation 1 refer to (Langmuir) adsorption, thermal desorption and electron dissociation, respectively, where F (molec/m2s) is the precursor flux, s the surface sticking coefficient, N0 (molec

• employed in FEBID for physisorption [1]. The ML model presented here assumes several simplifications. First, chemisorption processes considered are spontaneous; energy barriers for activated chemisorption, which can be modelled via the inclusion of Arrhenius terms in the sticking coefficient [29], are not

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• research for alternatives [29][30][31][32]. Mg is another dopant impurity [25][33][34][35][36][37][38] used for p-type doping with a low diffusion coefficient, which has a solid solubility of 1 × 1019 cm−3 and a low sticking coefficient (10−2–10−5) in the substrate temperature range of 725–850 K [34]. The

Bi-layer sandwich film for antibacterial catheters

• Gerhard Franz,
• Florian Schamberger,
• Hamideh Heidari Zare,
• Sara Felicitas Bröskamp and
• Dieter Jocham

Beilstein J. Nanotechnol. 2017, 8, 1982–2001, doi:10.3762/bjnano.8.199

• (approx. 100 mTorr) [33]. It should be noted that the reaction is not diffusion-controlled [59]. The rate at which the radicals strike the surface was estimated to exceed that at which a radical is effectively absorbed by the growing chain by approximately three orders of magnitude [57]. This low sticking

• coefficient is mandatory for the excellent conformal coating, and the rate-limiting step happens on the surface. As our interest is focused on layers with a defined porosity, which can only be achieved by a low deposition rate, diluting the chain-building vapor with an inert gas is one possibility to enhance

Process-specific mechanisms of vertically oriented graphene growth in plasmas

• Subrata Ghosh,
• Shyamal R. Polaki,
• Niranjan Kumar,
• Sankarakumar Amirthapandian,
• Mohamed Kamruddin and
• Kostya (Ken) Ostrikov

Beilstein J. Nanotechnol. 2017, 8, 1658–1670, doi:10.3762/bjnano.8.166

• bonds and open co-valency of carbon atoms, which affects the diffusion and adsorption of carbon atoms. Further, growth takes place by the material supplied through diffusion-assisted adsorption of carbon atoms at the edges of the nanosheets. Moreover, the sticking coefficient of the carbon adatoms

Vapor deposition routes to conformal polymer thin films

• Priya Moni,
• Ahmed Al-Obeidi and
• Karen K. Gleason

Beilstein J. Nanotechnol. 2017, 8, 723–735, doi:10.3762/bjnano.8.76

• deposition. Another approach to reduce the sticking coefficient is to increase the substrate temperature to hinder monomer adsorption. The functional dependence of temperature on Γ is seen in Equation 3 and plotted in Figure 3a. While a reduction both in chamber pressure or increase in substrate temperature

• , and Γi are the diffusivity, concentration at pore entrance, and sticking coefficient of species i respectively. The Thiele modulus can then be used to modify Fick’s second law to yield the following equation describing the concentration profile at position x down the pore’s length: with dimensionless

• initiator sticking coefficients has a substantial impact on the final value of step coverage for a given aspect ratio. Numerical solutions to Equation 6 are plotted in Figure 5a. High step coverage at higher aspect ratios requires the monomer sticking coefficient to be substantially smaller than the

Continuum models of focused electron beam induced processing

• Milos Toth,
• Charlene Lobo,
• Vinzenz Friedli,
• Aleksandra Szkudlarek and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1518–1540, doi:10.3762/bjnano.6.157

• temperature. The simplest case of gas-molecule adsorption onto a substrate surface is that of physisorption, described by a single potential well at the surface as shown in Figure 2. The flux Λa of precursor molecules physisorbing to vacant surface sites is given by: where sa is the sticking coefficient (in

• ): where sc is the sticking coefficient for activated sticking of gas molecules into the chemisorbed state (in the limit of zero surface coverage), s0 is the preexponential factor (i.e., the sticking coefficient for the limiting case of Econv − Ep = 0), and Tg is the temperature of the precursor gas

Influence of size, shape and core–shell interface on surface plasmon resonance in Ag and Ag@MgO nanoparticle films deposited on Si/SiO_x

• Sergio D’Addato,
• Daniele Pinotti,
• Maria Chiara Spadaro,
• Guido Paolicelli,
• Vincenzo Grillo,
• Sergio Valeri,
• Luca Pasquali,
• Luca Bergamini and
• Stefano Corni

Beilstein J. Nanotechnol. 2015, 6, 404–413, doi:10.3762/bjnano.6.40

• to the presence of the original Ag NPs. As observed on Ni@MgO [22] and FePt@MgO [23], MgO preferentially grows around the NPs. This is due to a much higher sticking coefficient of the metal compared to the inert Si/SiOx surface, and the MgO tends to form a matrix embedding the original particles. The

Advances in NO₂ sensing with individual single-walled carbon nanotube transistors

• Kiran Chikkadi,
• Matthias Muoth,
• Cosmin Roman,
• Miroslav Haluska and
• Christofer Hierold

Beilstein J. Nanotechnol. 2014, 5, 2179–2191, doi:10.3762/bjnano.5.227

• the increased sticking coefficient (by two orders of magnitude) compared to pristine nanotube devices that were also reported by the same group elsewhere [42]. This has the effect of increasing the sensitivity of the nanotube–PEI composite which makes it sensitive to NO2 concentrations as low as 100

Modeling and optimization of atomic layer deposition processes on vertically aligned carbon nanotubes

• Nuri Yazdani,
• Vipin Chawla,
• Eve Edwards,
• Vanessa Wood,
• Hyung Gyu Park and
• Ivo Utke

Beilstein J. Nanotechnol. 2014, 5, 234–244, doi:10.3762/bjnano.5.25

• surface per unit area, i.e., the impingement rate, I(x,t), to the fraction of the CNT surface area available for the precursor adsorption, f(x,t), and to the probability, at which an impinging precursor molecule adsorbs and reacts on an adsorption site, i.e., the reactive sticking coefficient, Γ: where

• penetration depth is not greatly affected by the reactive sticking coefficient, which indicates that the impingement rate of the precursor molecules on the CNT surface is large compared to the rate, at which they diffuse into the CNT array. In Figure 3c the thickness of oxide coated per cycle is plotted with

• array and with a reactive sticking coefficient close to one, it can be assumed that all the precursor molecules adsorb at the first encounter with an unoccupied adsorption site [32]. In this scenario, the adsorption sites are filled up linearly in the x direction, and the precursor concentration is zero

The role of electron-stimulated desorption in focused electron beam induced deposition

• Willem F. van Dorp,
• Thomas W. Hansen,
• Jakob B. Wagner and
• Jeff T. M. De Hosson

Beilstein J. Nanotechnol. 2013, 4, 474–480, doi:10.3762/bjnano.4.56

• about three orders of magnitude larger than the consumption by the e-beam. Even when the sticking coefficient is smaller than 1, the transport of precursor molecules through the gas phase is sufficient to grow the dots, making the contribution from surface diffusion non-dominant in this experiment

Ni nanocrystals on HOPG(0001): A scanning tunnelling microscope study

• Michael Marz,
• Keisuke Sagisaka and
• Daisuke Fujita

Beilstein J. Nanotechnol. 2013, 4, 406–417, doi:10.3762/bjnano.4.48

• artificially introducing defects by Ar sputtering, that defects act as nucleation centres for Ni on HOPG [20]. In our case the sticking coefficient of Ni on the basal plane for low temperatures seems to be large enough to promote the nucleation on the basal plane even without additional defects. With

• valid. The clusters grow first to their maximum height and then new clusters are formed on the substrate. Therefore, the coverage will be significantly lower for very low Πf × t as no new clusters are formed. Another possibility for the deviations in Figure 2 could be a significantly lower sticking

• coefficient when only a small amount of Ni is deposited. In this case our assumption of the proportionality of Πf × t to the total amount of deposited Ni would be no longer valid. We have demonstrated that the size of the clusters does not depend on the evaporation condition. In order to support our claim, we

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• [22] where J is the precursor flux modified by the sticking coefficient s. The local growth rate R(r) of the deposit, assuming the volume V for the nonvolatile dissociation product of an individual precursor molecule, is then obtained from with tD denoting the beam dwell time. Valuable insight can be