Canulescu, Stela

Fæster, Søren

Schou, Jørgen

Metal and metal oxide films with controlled thickness from a fraction of a monolayer up more than 1000 nm and known stoichiometry can be produced by pulsed laser deposition (PLD) relatively easily, and (PLD) is now a standard technique in all major research labo-ratories within materials science. However, organic materials are usually not well suited for direct laser irradiation, since the organic molecules may suffer from fragmentation by the laser light. We have, therefore, explored the possible fragmentation of organic molecules by attempting to produce thin films of C60 which is a strongly bound carbon molecule with a well-defined mass (M = 720 amu) and therefore a good, organic test molecule. C60 fullerene thin films of average thickness of more than 100 nm was produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was di-rected onto a frozen target of the matrix material, anisole, with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2, a dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. High-resolution SEM images of MAPLE deposited films reveal large circular features on the surface with high amount of material concentrated at edges. These features, observed over a wide range of laser flu-ences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in production of films with smooth surfaces and minimal contamination

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                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   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 orbit.dtu.dk on: Dec 19, 2017Growth of thin fullerene films by Matrix Assisted Pulsed Laser EvaporationCanulescu, Stela; Schou, Jørgen; Fæster, SørenPublication date:2011Document VersionEarly version, also known as pre-printLink back to DTU OrbitCitation (APA):Canulescu, S., Schou, J., & Fæster, S. (2011). Growth of thin fullerene films by Matrix Assisted Pulsed LaserEvaporation. Abstract from The second Nordic physics meeting : Sharing methods, exchanging ideas, Helsinki,Finland, .GROWTH OF THIN FULLERENE FILMS BY MATRIX ASSISTED PULSED LASER EVAPORATION   S. Canulescu, Jørgen. Schou  and S. F. Nielsenc  DTU Fotonik, Risø Campus, Technical University of Denmark, DK-4000 Roskilde,  Denmark, (c)Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark email: josc@fotonik.dtu.dk    Metal and metal oxide films with controlled thickness from a fraction of a monolayer  up more than 1000 nm and known stoichiometry can be produced by pulsed laser deposition (PLD) relatively easily, and (PLD) is now a standard technique in all major research labo-ratories within materials science. However, organic materials are usually not well suited for direct laser irradiation, since the organic molecules may suffer from fragmentation by the laser light. We have, therefore, explored the possible fragmentation of organic mole-cules by attempting to produce thin films of C60 which is a strongly bound carbon molecule with a well-defined mass (M = 720 amu) and therefore a good, organic test molecule.   C60 fullerene thin films of average thickness of more than 100 nm was produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was di-rected onto a frozen target of the matrix material, anisole, with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2, a dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. High-resolution SEM images of MAPLE deposited films reveal large circular features on the surface with high amount of material concentrated at edges. These features, observed over a wide range of laser flu-ences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in production of films with smooth surfaces and minimal contamination.  

Growth of thin fullerene films by Matrix Assisted Pulsed Laser Evaporation

C60 fullerene thin films of average thickness of more than 100 nm on silicon substrates can be produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target of anisole with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2 the dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. For high fluences high-resolution SEM images of MAPLE deposited films reveal large circular features on the surface with high amount of material concentrated at edges. These features, observed over a wide range of laser fluences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in films with smooth surfaces and minimal contamination

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   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 orbit.dtu.dk on: Dec 19, 2017Growth of thin fullerene films by matrix assisted pulsed laser evaporationCanulescu, Stela; Schou, Jørgen; Fæster, SørenPublication date:2011Document VersionEarly version, also known as pre-printLink back to DTU OrbitCitation (APA):Canulescu, S., Schou, J., & Fæster, S. (2011). Growth of thin fullerene films by matrix assisted pulsed laserevaporation. Abstract from E-MRS Spring Meeting ICAM & E-MRS / MRS Bilateral Conference on Energy :Technical sessions, Nice, France, .Growth of thin fullerene films by matrix assisted pulsed laser evaporation   S. Canulescu(a,b)Department of Photonics Engineering, Risø Campus, Technical University of Denmark, DK-4000 Roskilde, Denmark 1,a ,*, J. Schou1,b, and S.F. Nielsen2,c (c)Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark astec@fotonik.dtu.dk, bjosc@fotonik.dtu.dk, csfni@risoe.dtu.dk *Corresponding author  C60 fullerene thin films of average thickness of more than 100 nm on silicon substrates can be produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target of anisole with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2 the dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. For high fluences high-resolution SEM images of MAPLE deposited films reveal large circular features on the surface with high amount of material concentrated at edges. These features, observed over a wide range of laser fluences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in films with smooth surfaces and minimal contamination.   

Growth of thin fullerene films by matrix assisted pulsed laser evaporation

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Growth of thin fullerene films by matrix assisted pulsed laser evaporation

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