Boson Peak Investigation of Unusually Disproportionated Amorphous Silicon Monoxide via Terahertz Spectroscopy

To investigate multi-boson peaks (multi-BP), terahertz time-domain spectroscopy was performed on amorphous silicon monoxide (a-SiO), which exhibits unusual disproportion in the nanoscale region where the SiO2 and Si regions are separated. In the resulting THz spectrum, the BP was observed at 2.4 THz, as a broad asymmetric peak, and the BP frequency was evidently higher than that of silica glass. The results suggest that the higher BP frequency of a-SiO in the infrared spectrum originates from the a-Si cluster region.