Thermally Annealed in Vacuum Undoped and Al-Doped ZnO Thin Films for Multifunctional Applications
Undoped and Al-doped ZnO thin films have been prepared by spray pyrolysis in oxygen and argon atmospheres. The structural properties of ZnO thin films were investigated using atomic force microscopy (AFM) and X-ray diffraction (XRD). The optical properties were studied by UV-VIS spectroscopy and photoluminescence (PL) at room temperature. The electrical resistivity and Hall mobility were measured using the van der Pauw technique at room temperature. AFM studies show that the ambient atmosphere influences the roughness parameters of the ZnO surfaces. The XRD results revealed that undoped and Al-doped ZnO films are polycrystalline and developed  preferred orientation. The best electrical parameters (conductivity, mobility carriers and carrier concentration) are obtained for 1.0 at % of Al-doped ZnO synthetized in Ar atmosphere. In all cases, the electrical parameters under Ar are higher than under O2 atmosphere, unless they are not doped. Different applications of undoped and Al-doped ZnO thin films are discussed.
KeywordsUndoped and Al-doped ZnO Spray pyrolysis Surface properties Optical and electrical properties Photoluminescence
The authors thank the Ministry of Education, Culture and Research of Republic of Moldova for funding the grant 15.817.02.39A. In addition, a part of this research is supported by Research Center for Biomedical Engineering through Cooperative Project, RIE, Japan. Authors also thank Vasile Botnariuc, Moldova State University for supplying InP/CdS solar cells and Mr. Miyake Taku, Graduate School of Integrated Science and Technology, Shizuoka University, for taking AFM images.
- 1.Tadatsugu, M., Hidehito, N., Shinzo, T.: Highly conductive and transparent aluminum doped zinc oxide thin films prepared by RF magnetron sputtering. Japanese J Appl Phys 23(5), 2 (1984)Google Scholar
- 2.Manifacier, J.C., Szepessy, L., Bresse, J.F., Perotin, M., Stuck, R.: In2O3: (Sn) and SnO2: (F) films - application to solar energy conversion part II—Electrical and optical properties. Mater. Res. Bull. 14(2), 163–175 (1979)Google Scholar
- 3.Zhilova, O.V., Pankov, S.Yu., Sitnikov, A.V., Kalinin, Yu.E., Volochaev, M.N., Makagonov, V.A.: Structure and electrophysical properties of thin-film SnO2–In2O3 heterostructure. J. Mater. Sci.: Mater. Electron. 30(13), 11859–1186 (2019)Google Scholar
- 5.Rosa, A.M., da Silva, E.P., Amorim, E., Chave, M., Catto, A.C., Lisboa-Filho, P.N., Bortoleto, J. R.: Growth evolution of ZnO thin films deposited by RF magnetron sputtering. J. Phys.: Conf. Ser. 370 012020 (2012)Google Scholar
- 13.Norton, D.P., Heo, Y.W., Ivill, M.P., et al.: ZnO: growth, doping & processing. Mater. Today 7(6), 34–40 (2004)Google Scholar
- 15.Belghit, K., Subhan, M.A, Rulhe, U., Duchemin, S., Bougnot: Sprayed ZnO thin Films as optical window in CuInSe2 based solar cells. J. Eur. Photovolt. Sol. Energy Conf. (1991)Google Scholar
- 18.Simaşchevici, A., Şerban, D., Bruc, L., Coval, A., Gorceac, L., Monaico, E., Usatîi, Iu.: Int. Sci. J. Altern. Energy Ecology ISJAEEET2, 3451–54 (2006)Google Scholar
- 19.Potlog, T., Botnariuc, V., Gorceac, L., Spalatu, N., Maticiuc, N., Raievschi, S.: The caracterization of the CdS-based solar cell heterojunctions. In: The Proceedings of the International Semiconductor Conference, 11–13 October, Sinaia, Romania, Vol. 01, pp. 105–108 (2010)Google Scholar
- 21.Larsen, J.K. et al.: Interference effects in photoluminescence spectra of Cu2ZnSnS4 and Cu(In,Ga)Se2 thin films. J. Appl. Phys. 118, 035307-1- 035307-9 (2015)Google Scholar