The influence of physical and technological magnetron sputtering modes on the structure and optical properties of CdS and CdTe films

• Published in: Semiconductor Physics Quantum Electronics & Optoelectronics
• Date: 2017
• ISSN: 1560-8034
• Main Authors: Khrypunov, G.S., Kopach, G.I., Harchenko, M.M., Dobrozhan, A.І.
• Format: Article
• Language: English
• Published: Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України 2017
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/214920
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: The influence of physical and technological magnetron sputtering modes on the structure and optical properties of CdS and CdTe films / G.S. Khrypunov, G.I. Kopach, M.M. Harchenko, A.І. Dobrozhan // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2017. — Т. 20, № 2. — С. 262-267. — Бібліогр.: 10 назв. — англ.

To create technology for the preparation of CdS and CdTe thin films by direct current magnetron sputtering, the influence of physical and technological condensation modes on the crystal structure and optical properties of these films was investigated. The laboratory method of DC magnetron sputtering with preheating of the target for the mentioned films on glass substrates was developed. We obtained the CdS layers with a hexagonal structure 150…200 nm thick under conditions when the plasma discharge current density was 1.1 mA/cm² and the deposition rate – 30…40 nm/min. The bandgap in the obtained CdS films is Eg = 2.38…2.41 eV. After annealing in vacuum, the optical transparency of CdS films reaches 80…90%, which allows the use of these films as a transparent window layer in solar cells based on heterojunctions of CdS/CdTe. When the plasma discharge current density is 2.2…5.4 mA/cm², and the deposition rate is 200 nm/min, we obtained CdTe layers with a hexagonal structure up to 5 µm thick. The transmittance of CdTe films with a hexagonal structure in the wavelength range of the visible spectrum is up to 5%, and in the infrared spectral range is about 60%. The bandgap in the obtained CdTe layers of different thickness is 1.52…1.54 eV. After chloride treatment as a result of the phase transition wurtzite–sphalerite, the investigated CdTe films contain only the stable cubic structure and can be used as a base layer of solar cells.