Influence of temperature on optical properties of electron-beam-evaporated ZnSe thin film

Gullu H. H., Isik M., Gasanly N., PARLAK M.

PHYSICA SCRIPTA, cilt.95, sa.7, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 95 Sayı: 7
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1088/1402-4896/ab8eef
  • Dergi Adı: PHYSICA SCRIPTA
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Chemical Abstracts Core, Compendex, INSPEC, zbMATH
  • Anahtar Kelimeler: thin film, temperature effects, optical properties, ZnSe, electron-beam evaporation, SOLAR-CELL, PHYSICAL-PROPERTIES, ZINC SELENIDE, DEPENDENCE, PERFORMANCE, CONSTANTS, THICKNESS
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Structural and optical properties of ZnSe thin films grown by electron-beam evaporation technique were reported in the present paper. X-ray diffraction pattern exhibited a single peak around 27 degrees which is well-suited with cubic phase of the films. Energy dispersive X-ray spectroscopy analyses resulted in atomic composition ratio of Zn/Se nearly 1.0 which corresponds to the chemical formula of ZnSe. Transmission experiments were performed at various temperatures in between 10 and 300 K. The analyses of the transmission data showed that direct band gap energy of the ZnSe thin films increases from 2.72 to 2.83 eV as temperature was reduced to 10 K from room temperature. The Varshni and O'Donnell-Chen models giving the temperature-band gap energy relation were used to get various optical parameters of the evaporated thin films. Analyses resulted in absolute zero temperature band gap energy as 2.83 eV, temperature coefficient as -5.8 x 10(-4) eV K-1 and average phonon energy as 16 meV. Urbach tail state energies were also calculated using absorption coefficient in the low photon energy region as increasing from 173 meV (300 K) to 181 meV (10 K) with decreasing ambient temperature.