Anomalous temperature dependent photoluminescence properties of CdS x Se1−x quantum dots

CdS x Se1−x quantum dots were fabricated by a simple spin-coating heat volatilization method on InP wafer. Temperature dependent photoluminescence of CdS x Se1−x quantum dots was carried out in a range of 10–300 K. The integrated photoluminescence intensity revealed an anomalous behavior with increasing temperature in the range of 180–200 K. The band gap energy showed a redshift of 61.34 meV when the temperature increased from 10 to 300 K. The component ratio of S to Se in the CdS x Se1−x quantum dots was valued by both the X-ray diffraction data and photoluminescence peak energy at room temperature according to Vegard Law. Moreover, the parameters of the Varshni relation for CdS0.9Se0.1 materials were also obtained using photoluminescence peak energy as a function of temperature and the best-fit curve: α = (3.5 ± 0.1)10−4 eV/K, and β = 210 ± 10 K (close to the Debye temperature θ D of the material).