Influence of Thickness on Electrical and Optical Properties of Tellurium Thin Films Deposited by Chemical Spray Pyrolysis

Abstract

In this paper, Spray pyrolysis was applied to deposit Tellurium thin film on glass substrates at 498 ± 283 K in order to investigate the influence of thickness on the electrical and optical properties of the prepared thin films. The film thicknesses were measured in situ by weighting method. The thicknesses were from (150 to 800) nm.  X-ray diffraction results showed that the Te thin films formed were polycrystalline with hexagonal structure. The effect of film thickness on the electrical properties of the films was investigated by Hall Effect measurement through the analysis of the I-V plots. The conductivity of the films and carrier concentration were highly increased when the films became thicker. Transmission and absorption spectrum of the prepared thin film had been recorded using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300 - 2000 nm. The values of some important optical parameters of the studied films (absorption coefficient, and optical band gap energy) were determined using these spectra. The transmittance showed better results when thicknesses were being increased. In addition, the absorption coefficient is higher for thinner films and decreases for thicker films showing little dependence for absorption coefficient on thin film thickness in infra-red region of the wavelength. It was found from the optical properties studies that the type of transition of Te film is direct transition. Also, the optical energy band gap was evaluated for different thicknesses. The results have shown that the optical energy band gap was increased by the increase of thickness. Experiments and measurement results are presented.

Keywords

• Tellurium; Thin film; Electrical properties; Optical properties; Hall Effect; Spray pyrolysis

Original Research Paper

Abstract

References

1. References
2. Allahverdi N. Tsiulyanu Tsiulyanu D, Marian S, Liess HD. Effect of annealing and temperature on the NO2 sensing properties of tellurium based films, Sensors and Actuators B.100 (3): 2004, pp. 380-386
3. Shashwati S, Muthe KP, Joshi N. Room temperature operating ammonia sensor based on tellurium thin films, Sensors and Actuators B. 98(2−3): 2004, pp. 154−159. 334-338.
4. Ramesh A .N., KambhampatiTsiulyanu D, Marian S, Miron V. High sensitive tellurium based NO2 gas sensor. Sensors and Actuators” B.73 (1): 2001, pp. 35-42.
5. Josef P, Dana P, Jaroslav B, et all. Nano-structured crystalline Te films by laser gas-phase pyrolysis of dimethyl tellurium, Anal Appl Pyrolysis. 71(2): 2004, pp. 739−746.
6. -
7. Lozzi L, Santucci S, DI Nardo S. XPS, LEED and AFM investigation of the Si (100) surface after the deposition and annealing of tellurium thin films, Surface Science, 1996, pp. 352−354:1996.
8. Lozzi L, DI Nardo S, Passacantando M. Electron spectroscopy investigation of Te thin films deposited at room temperature on Si(100), Surface Science, 1995, pp. 331−333 (1): 569

9. Lozzi L, DI Nardo S, Passacantando M. Growth of Te thin films deposited at room temperature on the Si (100) 2×1 surface, J. of Electron Spectroscopy and Related Phen. 71(1): 39, 1995.
10. Tsiulyanu D. , Mocreac O. Impedance Spectroscopy of Sensitive to Harmful Gases Tellurium Thin Films, Journal of Non-Oxide Glasses, Vol. 3. No. 2, April- June 2011, pp. 43-50.
11. Peterson M. J, Cocks F. H. Tellurium Selective Absorber Surfaces" Mater. Sci. & Engineering Vol. 41, 1979, pp. 143-147.
12. Janan H. S., Optical Properties of Tellurium Thin Film Prepared by Chemical Spray Pyrolysis Method, Journal of Kufa- Physics Vol.3 No.2, 2011.
13. Mahdi H.S., Souad G.K. Marwa R. F. Structural and electrical properties of tellurium thin films prepared by vacuum thermal deposition, Iraqi Journal of Physics, Vol. 10, No.17, 2012, PP. 7-11.
14. Dinesh C., Rajendra K. and Ram M. Influence of Thickness on Optical Properties of As2Se3 Thin Films” Turk J Phys., 30,(2006 ,pp. 519 – 527.
15. Rusu M. On the Electrical and Optical Properties of the Stratified Tellurium Thin Film" Journal of Optoelectronics and Advanced Materials, Vol. 3, No 4, Dec. 2001, p 867-872.
16. Balasubram T. Narayandass K. Mangalaraj D. Electrical Properties of Thermally Evaporated Tellurium Thin Films, Bulletin of Materials Science. February 1997, Volume 20, Issue 1, pp 79-92.
17. Celalettin Baykul M. , Nilgun O. Band alignment of Cd(1−x)ZnxS produced by spray pyrolysis method, Thin Solid Films 518, 2010, pp. 1925–1928.
18. Janan H. S. Chemical Spray Deposition for Tellurium Thin Film” Journal of Babylon University/Engineering Sciences/ No.(3)/ Vol.(21): 2013.
19. Celalettin Baykul M. , Nilgun O. Band alignment of Cd (1−x)ZnxS produced by spray pyrolysis method, Thin Solid Films 518, 2010, pp. 1925–1928.
20. Giraldi, T.R., Escote M.T. et. Effect of Thickness on the Electrical and Optical Properties of Sb Doped SnO2(ATO) Thin Films, Journal of Electroceramics, 13, 2004, pp. 159–165.
21. Encyclopedia of chemical technology Tellurium and Tellurium Compounds",Vol. 22, pp. 658-673, John Wiley& Sons Inc., New York, 1980.
22. Powder Diffraction File, Joint Committee on Powder Diffraction Standards, International Center for Diffraction Data, Swarthmore, Pa., File (4-0554).
23. Shadia J. Riyad N. Effect of Film thickness on the Electrical and Structural Properties of CdS: In Thin Films” American Journal of Applied Sciences 5 (9): 2008, pp. 1141-1143.
24. .