Control of structures of deposited polymer films by ablation laser wavelength: Polyacrylonitrile at 308, 248, and 193 nm

Abstract

Articles you may be interested inEffect of SiO2 buffer layers on the structure of SrTiO3 films grown on silicon by pulsed laser deposition Molecular beam deposited thin films of pentacene for organic field effect transistor applications Extensive control of structures of deposited polymer films has been realized when the films have been prepared on a quartz or KBr substrate by laser ablation of polyacrylonitrile ͑PAN͒ with 308 ͑XeCl͒, 248 ͑KrF͒, and 193 nm ͑ArF͒ excimer laser beams, as revealed by scanning electron microscopy, infrared spectroscopy, x-ray photoelectron spectroscopy, electron spin resonance, and x-ray diffraction measurements. The original structure of PAN is essentially retained for the films deposited by ablation at 308 nm. Deformation and elimination of nitrile groups occur for the films prepared by ablation at 248 and 193 nm, respectively. Furthermore, a remarkable power-dependent structural change has been observed at 248 nm; an increase in the laser power has led to ring closure of nitrile groups, resulting in the development of -conjugated systems. In addition, a rather high electric conductivity on the order of 10 Ϫ2 S cm Ϫ1 has been given to the films deposited by ablation at 248 and 193 nm on reirradiation with lower-power excimer laser beams of 308 nm.

Pulsed laser deposition of liquid crystals

“…3͒. The retention of the cyano group under 193 nm irradiation contrasts with work on ablation of Polyacrylonitrile 5 , and may be a result of the much lower fluence used here ͑ϳ30 mJ/cm 2 .cf. Ͼ170 mJ/cm 2 in Ref.…”

“…2 In contrast, except for some polymers, [3][4][5] the application of PLD to organic compounds has been less widely investigated. This stems, in part, from the existence of photodisociative processes during the laser target/plume interaction 5,6 that may alter the chemical properties of the deposited films, although PLD has recently been applied successfully to complex organic compounds such as Pentacene, 7 Copper-phthalocyanine and 4-dialkylamine-4'-nitrostilbene. 8 The aim of work reported here was to evaluate the suitability of PLD for the deposition of LC thin films and to investigate the influence of laser fluence and wavelength on the properties of the deposited material.…”

Preparation of organic semiconductive thin films by laser ablation: Control of structure and electric properties by selecting wavelength, fluence, and substrate temperature

“…For example, we obtained several structurally distinct polymer films by excimer laser ablation (ELA) of polyacrylonitrile (PAN), essentially pristine films with the original structure of PAN, and those without a CN group, selectively [9].…”

Preparation of Polyacenic Semiconductor (PAS) Thin Films by Excimer Laser Ablation of Bulky PAS Materials.

“…[4][5][6] we have succeeded in preparation of high quality PAS films on substrates at several temperatures ( T,.) by excimer laser ablation (ELA) of PF resin and/or bulky PAS obtained by pyrolysis of PF resin at various T~, .…”