Study of thermal and optical properties of the Ge-Te-CdI2/ZnI2 far infrared transmitting glasses

A systematic series of (100 − x)(GeTe4.3) − xCdI2/ZnI2 far infrared transmitting glasses were prepared by traditional melt-quenching method. ZnI2 (20 mol%) can be introduced in the glassy matrix, while only 10 mol% CdI2 can be incorporated in the Ge-Te-CdI2 glass system. Based on differential thermal analysis (DTA) data, most of the glass samples have good thermal stability. A maximum ΔT value of 115 °C was obtained for the glass composition 90(GeTe4.3)–10ZnI2. The allowed indirect transition optical band gap was calculated according to the classical Tauc equation. It is found that the indirect optical band gap decreased from 0.619 to 0.569 eV with the CdI2 addition and increased from 0.628 to 0.677 eV with the ZnI2 addition. According to infrared transmission spectra, the Ge-Te-CdI2/ZnI2 glasses show wide IR transparency.