Synthesis of amorphous chalcogenide As-S-based films with arsenic content from 35 to 55 at. % by a PECVD method is achieved. The composition-structure-optical properties relationship is revealed. Varying the composition of the films from As35S65 to As55S45 is accompanied by a change of the dominant structural units: from AsS3/2 pyramids to cage-like As4S4 and As4S3 units, causing a considerable decrease of the optical band gap from 2.42 to 1.87 eV. It has been found out that modification by a focused laser irradiation (473 nm) leads to formation of micro/nanocrystalline inclusions feasible for applications in medicine, optoelectronics and integrated optics. The type of inclusions depends on the dominant structural units of the initial films. In case of the As55S45 film appearance of the dimorphite crystalline phase (α-As4S3) is observed. The ex-situ laser modification of the As-S films leads to appearance of a photoluminescence emission, and its maximum position shifts from 1.8 to 2.05 eV depending on the initial film stoichiometry.

Impact of composition and ex-situ laser irradiation on the structure and optical properties of As-S-based films synthesized by PECVD

De Filpo G.;
2019

Abstract

Synthesis of amorphous chalcogenide As-S-based films with arsenic content from 35 to 55 at. % by a PECVD method is achieved. The composition-structure-optical properties relationship is revealed. Varying the composition of the films from As35S65 to As55S45 is accompanied by a change of the dominant structural units: from AsS3/2 pyramids to cage-like As4S4 and As4S3 units, causing a considerable decrease of the optical band gap from 2.42 to 1.87 eV. It has been found out that modification by a focused laser irradiation (473 nm) leads to formation of micro/nanocrystalline inclusions feasible for applications in medicine, optoelectronics and integrated optics. The type of inclusions depends on the dominant structural units of the initial films. In case of the As55S45 film appearance of the dimorphite crystalline phase (α-As4S3) is observed. The ex-situ laser modification of the As-S films leads to appearance of a photoluminescence emission, and its maximum position shifts from 1.8 to 2.05 eV depending on the initial film stoichiometry.
Arsenic sulfide; Chalcogenide films; Nanocrystals formation; Optical properties; PECVD
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/295787
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