Refractive index change caused by electron irradiation in amorphous As–S and As–Se thin films coated with different metals

Abstract

The refractive index change caused by electron irradiation was measured in amorphous As–S and As–Se thin films coated with different metals. Metal atoms/ions diffused into the films during irradiation. The diffusion was dependent on the metal and influenced the refractive index. The influence was smallest in As40S60 films although these films possessed the highest overall refractive index changes. Au atoms/ions were almost immobile in all films while Ag atoms/ions had the highest mobility. Their high mobility allowed them to diffuse laterally within the film.

Electron irradiation induced reduction of the permittivity in chalcogenide glass (As2S3) thin film

“…The observed measurements, and the calculated optical properties therein, are extraordinary, in the sense that all previously published experiments, with high energy electrons (40 keV), reported an increase in the refractive index between 3% and 8%. [27][28][29][30][31]49 In contrast to the vast literature reporting photon-induced refractive index change, which has yielded as much as an 8% increase in the refractive index of As 2 S 3 film under illumination, 13,15 in our experiment the refractive index decreases as much as 23%. Bearing in mind that the conditions in the cited experiments are significantly different from those reported here, we believe that the discrepancy could be explained by two different mechanisms.…”

“…Suhara et al 27 found a maximum change of Dn=n ¼ þ3:6%, with no significant modification in the thickness of the film. On the other hand, Nordman et al [28][29][30] and Tanaka et al 31 independently observed a $3% increment in the refractive index of chalcogenide glass; simultaneously the formation of trenches and mounds, 180 nm and 110 nm, respectively, in chalcogenide films of 5 À 11 lm thick, was observed. They posited that the morphological and optical alteration derives from the structural reorganization and re-bonding of the homopolar and heteropolar bonds, in addition to the electrostatic effects arising from the charge density variation.…”

“…They posited that the morphological and optical alteration derives from the structural reorganization and re-bonding of the homopolar and heteropolar bonds, in addition to the electrostatic effects arising from the charge density variation. [28][29][30][31] Whilst many of these effects appeal to our research interest, we are particularly intrigued by the alteration in the optical properties of chalcogenide glass thin films, and its possible applications. However, in most of the previous studies only the refractive index has been characterized, with little information available on how the electromagnetic components, i.e., permittivity and permeability, reshape under energy absorption.…”

Perspective and potential of smart optical materials

“…These smart optical materials (SOM) change properties based on one of the following properties or effects: Electro-or magneto-absorption changes, [1,2] the Franz-Keldysh effect, [3] the quantum-confined Stark effect, [4] the Zeeman effect, [5] the electrochromic effect, [6] the Pockels effect, [7] the Kerr effect, [8] electro or magneto gyration, [9,10] the electronrefractive effect. [11,12] When an electromagnetic (EM) wave propagates through a medium that has a property of smart optical materials, the wave nature can be altered by an applied field. Such a change may appear as spectral shift of the incident EM wave and/or as a shift in refractive index.…”

Effect of Heat Treatment on the ac Conductivity and Dielectric Properties of Ag33Sb31Se36Thin Films

“…Little attention has been paid to the ternary compound of the type A I B V C VI [12][13][14] including AgSbSe system. Recently, we have published two papers on the studies of Ag 33 Sb 31 Se 36 system [15,16].…”