Determination of thermal diffusivity and optical gap of an amorphous P20Se80 alloy through photoacoustic measurements

We investigated the thermal diffusivity and optical properties at room temperature of an amorphous P20Se80 alloy produced by mechanical alloying considering two apparatuses based on the photoacoustic technique. The room temperature thermal diffusivity αs of P20Se80 was determined using the open photoacoustic cell configuration considering the thermal diffusion and thermoelastic bending effects, and we found that P20Se80 has the highest reported value of αs among amorphous alloys produced by mechanical alloying. The optical absorption and the optical gap were obtained through a photoacoustic spectroscopy apparatus, and the optical gap was determined to be in the near infrared region. The alloy presents strong absorption in the UV and visible regions, which suggests possible applications in heat transfer or cooling devices, and photodetectors.