Preparation and Photosensitivity of Samarium Sulfide Thin Films

概要

論文の詳細を見る
Metallic SmS and Sm3S4 thin films, in which Sm ions possess divalent and trivalent mixed state, were prepared on Si wafer substrate at 20°C using Sm2S3 and Sm2S3/Sm mixed targets by rf magnetron sputtering. Even though only Sm3S4 phase was formed using a Sm2S3 target, both metallic SmS and Sm3S4 films were deposited using Sm2S3/Sm mixed targets depending on substrate positions. The possible formation processes of metallic SmS and Sm3S4 thin films were proposed. Irradiation experiments were performed using a femtosecond laser at 800 nm with a pulse duration of 120 fs and a repetition rate of 10 Hz. No macroscopic changes were observed in Sm3S4 thin films at a fluence <1.2×104 J•m-2 and the film ablation occurred over 1.2×104 J•m-2. On the other hand, in the case of metallic SmS films, with the fluence of 5.0×103 J•m-2, the metallic to semiconductor phase transition occurred, and the film ablation occurred when the fluence was over 7.0×103 J•m-2. X-ray photoelectron spectroscopy study revealed that Sm2+ (4f) peak near the Fermi energy was shifted about 0.3 eV in the irradiated metallic SmS film. The change in the electronic structure change of Sm for the films was discussed.
公益社団法人日本セラミックス協会の論文