Photoinduced structural changes in As₁₀₀₋xSx layers

• Published in: Semiconductor Physics Quantum Electronics & Optoelectronics
• Date: 2000
• Main Authors: Stronski, A., Vlcek, M., Sklenar, A.
• Format: Article
• Language: English
• Published: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2000
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/121137
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Photoinduced structural changes in As₁₀₀₋xSx layers / A. Stronski, M. Vlcek, A. Sklenar // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2000. — Т. 3, № 3. — С. 394-399. — Бібліогр.: 29 назв. — англ.

The present paper is concerned with investigations of photoinduced structural changes in As100-xSx layers. Optical constants of variously treated (virgin, exposed, annealed) samples were determined from optical transmission measurements in the spectral region 400-2500 nm. The energy dependence of refractive index n for variously treated samples was fitted by the Wemple-DiDomenico dispersion relationship and used to estimate the single-oscillator model parameters. It was found, that exposure, as well as annealing leads to the increase in n values over the all investigated spectral region. Compositional dependencies of single-oscillator model parameter Ed (dispersion energy), optical dielectric constant ε(0) show maximum at stoichiometric composition As₄₀S₆₀ and, possibly, weak maximum at As₂₈.₆S₇₁.₄ composition. Changes of the parameters of the single-oscillator model induced by treatment are discussed on the base of photo- and thermally-induced structural changes, which were directly confirmed by Raman scattering measurements. Such photoinduced structural changes provide good etching selectivity of As-S layers in amine based solvents. Intensity dependence of the Raman bands corresponding to the As rich and S rich molecular fragments on exposure time is well described by the exponential decay, which correlates with exponential decay dependence of the etching rate of As₁₀₀₋xSx layers on exposure.