A comparative investigation on growth, nanostructure and electrical properties of copper oxide thin films as a function of annealing conditions
Tóm tắt
This paper is an attempt to compare the influence of various annealing conditions on growth, nanostructure, surface morphology and electrical properties of copper oxide thin films. Cu thin films of 85 nm thickness were deposited on glass substrate by thermal evaporation method, and then post-annealed at different environments (air and oxygen flow), different temperatures (200–400 °C) and different times (35 and 75 min). X-ray diffraction results showed (Cu2O) cuprite phase for all annealed samples at 200 and 250 °C and (CuO) tenorite phase for all samples annealed under different conditions at 350 and 400 °C. A complex phase of CuO and Cu2O was observed for all annealed samples at 300 °C, with exception for the sample annealed with flow of oxygen for 75 min. The atomic force microscopy results showed that surface morphology of the samples was strongly affected by the changes of annealing conditions (i.e., time, temperature and environment). The size of the grains increased with annealing temperature and time, while the samples annealed with oxygen flow showed larger grains than those annealed in air. Two different behaviors with annealing temperature were distinguished for the surface roughness of the samples annealed in the air and those annealed with flow of oxygen. Resistivity and Hall effect of samples were measured by a four-point probe instrument and a Hall effect investigation system, respectively. The electrical analyses showed that the variations in annealing conditions had a remarkable effect on measured electrical parameters, namely films resistivity, carriers concentration and type, and Hall mobility.
Tài liệu tham khảo
Mohemmed Shanid, N.A., Abdul Khadar, M.: Evolution of nanostructure, phase transition and band gap tailoring in oxidized Cu thin films. Thin Solid Films 516, 6245–6252 (2008)
Ray, S.C.: Preparation of copper oxide thin film by the sol–gel-like dip technique and study of their structural and optical properties. Sol. Energy Mater. Sol. Cells 68, 307–312 (2001)
Figueiredo, V., Elangovan, E., Goncalves, G., Barquinha, P., Pereira, L., Franco, N., Alves, E., Martins, R., Fortunato, E.: Effect of post-annealing on the properties of copper oxide thin films obtained from the oxidation of evaporated metallic copper. Appl. Surf. Sci. 254, 3949–3954 (2008)
Koffyberg, F.P., Benko, F.A.: A photoelectrochemical determination of the position of the conduction and valence band edges of p-type CuO. J. Appl. Phys. 53, 1173–1175 (1982)
Serin, N., Serin, T., Horzum, S., Celik, Y.: Annealing effects on the properties of copper oxide thin films prepared by chemical deposition. Semicond. Sci. Technol. 20, 398–401 (2005)
Gan, Z.H., Yu, G.Q., Tay, B.K., Tan, C.M., Zhao, Z.W., Fu, Y.Q.: Preparation and characterization of copper oxide thin films deposited by filtered cathodic vacuum arc. J. Phys. D Appl. Phys. 37, 81–85 (2005)
Kari Brown, E.R., Choi, K.: Synthesis and characterization of transparent nanocrystalline Cu2O films and their conversion to CuO films. Chem. Commun. 31, 3311–3313 (2006)
Borzi, R.A., Stewart, S.J., Mercader, R.C., Punte, G., Garcia, F.: Magnetic behavior of nanosized cupric oxide. J. Magn. Magn. Mater. 226–230, 1513–1515 (2001)
Balamurugan, B., Mehta, B.R., Avasthi, D.K., Singh, F., Arora, A.K., Rajalakshmi, M., Raghavan, G., Tyagi, A.K., Sivaprasad, S.M.: Modifying the nanocrystalline characteristics-structure, size, and surface states of copper oxide thin films by high-energy heavy-ion irradiation. J. Appl. Phys. 92, 3304–3310 (2002)
Wang, W., Liu, Z., Liu, Y., Xu, C., Zheng, C., Wang, G.: A simple wet-chemical synthesis and characterization of CuO nanorods. Appl. Phys. A 76, 417–420 (2003)
Nair, M.T.S., Guerrero, L., Arenas, O.L., Nair, P.K.: Chemically deposited copper oxide thin films: structural, optical and electrical characteristics. Appl. Surf. Sci. 150, 143–151 (1999)
Oral, A.Y., Mensur, E., Aslan, M.H., Basaran, E.: The preparation of copper(II) oxide thin films and the study of their microstructures and optical properties. Mater. Chem. Phys. 83, 140–144 (2004)
Alkoy, E.M., Kelly, P.J.: The structure and properties of copper oxide and copper aluminium oxide coatings prepared by pulsed magnetron sputtering of powder targets. Vacuum 79, 221–230 (2005)
Pierson, J.F., Thobor-Keck, A., Billard, A.: Cuprite, paramelaconite and tenorite films deposited by reactive magnetron sputtering. Appl. Surf. Sci. 210, 359–367 (2003)
Balamurugan, B., Mehta, B.R.: Optical and structural properties of nanocrystalline copper oxide thin films prepared by activated reactive evaporation. Thin Solid Films 396, 90–96 (2001)
Ghosh, S., Avasthi, D.K., Shah, P., Ganesan, V., Gupta, A., Sarangi, D., Bhattacharya, R., Assmann, W.: Deposition of thin films of different oxides of copper by RF reactive sputtering and their characterization. Vacuum 57, 377–385 (2000)
Yoon, K.H., Choi, W.J., Kang, D.H.: Photoelectrochemical properties of copper oxide thin films coated on an n-Si substrate. Thin Solid Films 372, 250–256 (2000)
Muthe, K.P., Vyas, J.C., Narang, S.N., Aswal, D.K., Gupta, S.K., Bhattacharya, D., Pinto, R., Kothiyal, G.P., Sabharwal, S.C.: A study of the CuO phase formation during thin film deposition by molecular beam epitaxy. Thin Solid Films 324, 37–43 (1998)
Santra, K., Sarker, C.K., Mukherjee, M.K., Ghosh, B.: Copper oxide thin films grown by plasma evaporation method. Thin Solid Films 213, 226–229 (1992)
Maruyama, T.: Copper oxide thin films prepared by chemical vapor deposition from copper dipivaloylmethanate. Sol. Energy Mater. Sol. Cells 56, 85–92 (1998)
Warren, B.E.: X-ray Diffraction. Addison Wesley Publishing Co., London (1969)
Savaloni, H., Player, M.A., Gu, E., Marr, G.: Influence of substrate temperature, deposition rate, surface texture and material on the structure of uhv deposited erbium films. Vacuum 43, 965–980 (1992)
vander Kolk, G.J., Verkerk, M.J.: Microstructural studies of the growth of aluminum films with water contamination. J. Appl. Phys. 59, 4062–4067 (1986)
Khojier, K., Savaloni, H., Kangarloo, H., Ghorannneviss, M., Yari, M.: Influence of annealing temperature on the nanostructure and corrosivity of Ti/stainless steel substrates. Appl. Surf. Sci. 254, 2528–2533 (2008)
Aspnes, D.E., Kinsbron, E., Bacon, D.D.: Optical properties of Au: sample effects. Phys Rev. B 21, 3290–3299 (1980)