The Mechanism of the Formation of Binary Compounds Between Zn and S Impurity Atoms in Si Crystal Lattice

The paper presents the results of an experimental study of surface morphology, elemental composition, electrophysical and optical properties of Si samples earlier doped with impurity atoms of Zn and S. The results of the study revealed a sufficient concentration of Zn and S elements on Si surface after diffusion (3.1% and 2.6% by weight, respectively). After additional thermal treatment at different temperatures, i.e., at 850°C and 875°C, the samples of I group have regained their initial parameters. However, it’s noteworthy that the mobility of charge carriers in group I samples was comparatively lower than that in group II samples allegedly under the influence of Zn and S binary molecules. After additional heat treatment of all samples at a temperature of 875°C, the authors have studied optical absorption coefficients. And their band gap energies were determined using the Tauc Plot method. According to the results of the study, the optical band gaps in group II and III samples were 1.12 eV, whereas the band gap energy in group I samples after additional thermal treatment at a temperature of 875 °C turned out to be 1.31 eV. Having theoretically calculated the band gap by applying Vegard’s law, the authors suggested that the new structure must be of Si0.92ZnS0.08 - type.