TY - JOUR

T1 - Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition

AU - Bulgakov, Alexander V

AU - Bykov, Nikolay Y

AU - Safonov, Alexey I

AU - Shukhov, Yuri G

AU - Starinskiy, Sergey V

N1 - Funding: The experimental part of the research was performed under a state contract with IT SB RAS. The theoretical work was carried out under financial support from the Ministry of Science and Higher Education of the Russian Federation as part of the World-Class Research Center Program for Advanced Digital Technologies (contract no. 075-15-2022-311). A.V.B. acknowledges financial support from the European Regional Development Fund and the state budget of the Czech Republic (Project BIATRI: CZ.02.1.01/0.0/0.0/15_003/0000445).

PY - 2023/7/7

Y1 - 2023/7/7

N2 - Supersonic jets of metal vapors with carrier gas are promising for producing nanostructured metal films at relatively low source temperatures and high deposition rates. However, the effects of the carrier gas on the jet composition and expansion dynamics, as well as on film properties, remain virtually unexplored. In this work, the free-jet expansion of a mixture of silver vapor with helium in a rarefied regime at an initial temperature of 1373 K is investigated through mass spectrometry and direct-simulation Monte Carlo methods. Introducing the carrier gas into the source is found to result in a transition from a collisionless to a collision-dominated expansion regime and dramatic changes in the Ag jet, which becomes denser, faster, and more forward-directed. The changes are shown to be favorable for the formation of small Ag clusters and film deposition. At a fairly high helium flow, silver Ag2 dimers are observed in the jet, both in the experiment and the simulations, with a mole fraction reaching 0.1%. The terminal velocities of silver atoms and dimers are nearly identical, indicating that the clusters are likely formed due to the condensation of silver vapor in the expanding jet. A high potential of supersonic Ag-He jets for the deposition of nanostructured silver films is demonstrated. The deposited jet Ag2 dimers appear to serve as nucleation centers and, thus, allow for controlling the size of the produced surface nanostructures.

AB - Supersonic jets of metal vapors with carrier gas are promising for producing nanostructured metal films at relatively low source temperatures and high deposition rates. However, the effects of the carrier gas on the jet composition and expansion dynamics, as well as on film properties, remain virtually unexplored. In this work, the free-jet expansion of a mixture of silver vapor with helium in a rarefied regime at an initial temperature of 1373 K is investigated through mass spectrometry and direct-simulation Monte Carlo methods. Introducing the carrier gas into the source is found to result in a transition from a collisionless to a collision-dominated expansion regime and dramatic changes in the Ag jet, which becomes denser, faster, and more forward-directed. The changes are shown to be favorable for the formation of small Ag clusters and film deposition. At a fairly high helium flow, silver Ag2 dimers are observed in the jet, both in the experiment and the simulations, with a mole fraction reaching 0.1%. The terminal velocities of silver atoms and dimers are nearly identical, indicating that the clusters are likely formed due to the condensation of silver vapor in the expanding jet. A high potential of supersonic Ag-He jets for the deposition of nanostructured silver films is demonstrated. The deposited jet Ag2 dimers appear to serve as nucleation centers and, thus, allow for controlling the size of the produced surface nanostructures.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85165083437&origin=inward&txGid=15c5fb1b3cd6cbfcc78b152780853071

U2 - 10.3390/ma16134876

DO - 10.3390/ma16134876

M3 - Article

C2 - 37445190

VL - 16

JO - Materials

JF - Materials

SN - 1996-1944

IS - 13

M1 - 4876

ER -