Fs Laser Patterning of Amorphous As2S3 Thin Films

• Published in: Materials Vol. 17; no. 4; p. 798
• Main Authors: Mihai, Claudia, Jipa, Florin, Socol, Gabriel, Kiss, Adrian E., Zamfirescu, Marian, Velea, Alin
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 07.02.2024
• Subjects: Arsenic; Arsenic trisulfide; Continuous radiation; Direct laser writing; Femtosecond pulses; Glass substrates; Gold; Heterostructures; Irradiation; Lasers; Microscopy; Morphology; Power; Pulsed laser deposition; Pulsed lasers; Thin films; United States > US
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17040798

This study investigates the morphological changes induced by femtosecond (fs) laser pulses in arsenic trisulfide (As2S3) thin films and gold–arsenic trisulfide (Au\As2S3) heterostructures, grown by pulsed laser deposition (PLD). By means of a direct laser writing experimental setup, the films were systematically irradiated at various laser power and irradiation times to observe their effects on surface modifications. AFM was employed for morphological and topological characterization. Our results reveal a clear transition threshold between photoexpansion and photoevaporation phenomena under different femtosecond laser power regimes, occurring between 1 and 1.5 mW, irrespective of exposure time. Notably, the presence of a gold layer in the heterostructure minimally influenced this threshold. A maximum photoexpansion of 5.2% was obtained in As2S3 films, while the Au\As2S3 heterostructure exhibited a peak photoexpansion of 0.8%. The study also includes a comparative analysis of continuous-wave (cw) laser irradiation, confirming the efficiency of fs laser pulses in inducing photoexpansion effects.