Possible mechanism of Ag photodiffusion in a‐As₂S₃ thin films

Abstract

Monitoring the silver photodiffusion in thin amorphous As2S3 film is addressed with a new experimental setup. A possible photo‐diffusion mechanism of silver into the a‐As2S3 thin film under green laser diode light (λ = 532 nm) irradiation is proposed. The proposed mechanism is based on a gradual filling of the structural voids existing in the network of the thin chalcogenide layer. This mechanism is supported by XRD measurements, optical absorption, and modeling data.

Kinetics of photo-dissolution within Ag/As2S3 heterostructure

“…These different stages are most visible in the spectrum for the sample with 40 nm Ag in Fig.4(a), which shows qualitative differences compared to the remaining three samples with smaller thicknesses. In fact, our experimental curve in Fig.4(a) is most similar to what was observed by Sava et al [28]. Here, photo-dissolution kinetics is not linear, but consists of different stages, each of which is identified by a characteristic slope in the rate of transmission change.…”

“…Then laser illumination helps to detach and transfer the Ag into the As2S3 matrix as Ag + ions. Continuous illumination causes a charge gradient, which then produces a preferential drift direction for the roaming Ag + ions, pushing them away from the interface, toward the inside of the As2S3 film [12,28] from EXAFS measurements. As a result, as these sites become filled photo-dissolution slows down and finally saturates.…”

Single-step synthesis of silver sulfide nanocrystals in arsenic trisulfide

“…Moreover, they present a variety of photosensitive phenomena, including photocrystallization, photodarkening, and photodiffusion, which have motivated numerous researches for decades [16,17]. Since the first observation of metal photodoping in ChGs, many studies have been performed on the diffusion mechanism of silver in amorphous arsenic trisulfide (As 2 S 3 ) [18][19][20]. Basically, by shining light on As 2 S 3 , in which a thin metallic layer of silver is deposited, Ag ions can readily dissolve, resulting in a homogeneous doped layer.…”

Laser Assisted Single Step Method to Synthesize Ag Nanoparticles on Chalcogenide Surface

“…First, on illumination of Se layer, electron-hole pairs are generated. The holes diffuse away to dark regions of the layer leaving behind negatively charged illuminated region and creating a Damber Voltage [6,8]. As the light penetrates into the Ag layer, its photo excitation leads to formation of Ag + ions.…”