Journal of Materials Science

, Volume 32, Issue 5, pp 1269–1275 | Cite as

D.C. I–V characteristics and steady-state photoconductivity of Au/Pb2CrO5/SnO2 sandwich-structure films under illumination in the visible region



The room temperature d.c. current–voltage (I–V) characteristics of an Au/Pb2CrO5/SnO2 sandwich-structure 1.39 μm thick film have been measured for d.c. voltages, Vd.c., in the range 0.25 V≤Vd.c.≤5.0 V. These measurements were carried out under both dark and visible-light illumination conditions. For Vd.c.<2.5 V, the I–V curves of the sample in both dark and light environments were found to be non-linear and conform to space-charge-limited (SCL) current governed by traps uniformly distributed in energy. At higher d.c. voltages, a nearly Mott–Gurney V2 behaviour of the dark current has been observed, whereas the I–V behaviour of the illuminated specimen was a combination of an ohmic conduction and a V2 dependence at low illumination levels and became highly ohmic at large light intensities. This behaviour can be understood in terms of a reduction in the SCL dark current in favour of a larger ohmic d.c. photocurrent as a result of neutralization of the majority-carrier space charge by the photogenerated minority carriers of the electron–hole pairs produced under the illumination with visible light of energy ℏω≅EG(∼2.1–2.3 eV for the Pb2CrO5 material). The d.c. photocurrent, Iphot, at a fixed d.c. voltage, was found to follow a power-law dependence on light intensity, F, of the form Iphot∝Fγ, with the exponent γ being dependent on the applied d.c. voltage. At the low-voltage side (Vd.c.<1.5 V), γ∼0.5, a value usually obtained when the photoconductivity behaviour is governed by bimolecular recombination mechanisms. As the d.c. voltage is increased further, γ increases monotonically until it saturates at a value of about 0.9 for d.c. voltages beyond 3.5 V, where monomolecular recombination processes seem to be more operative with increasing d.c. voltage.


Dark Current Illumination Level Ohmic Behaviour Ceramic Disc Ohmic Conduction 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    T. Negas, J. Am. Ceram. Soc. 51 (1968) 716.CrossRefGoogle Scholar
  2. 2.
    J. C. Ruckman, R. T. W. Morrison, and R. H. Buck, J. Chem. Soc. Dalton Trans. 426 (1972)Google Scholar
  3. 3.
    K. Toda and S. Morita, Appl. Phys. A33 (1984) 231.CrossRefGoogle Scholar
  4. 4.
    Idem, J. Appl. Phys. 55 (1984) 210.CrossRefGoogle Scholar
  5. 5.
    S. Morita and K. Toda, Appl. Phys. A36 (1985) 131.CrossRefGoogle Scholar
  6. 6.
    K. Toda and S. Morita, J. Appl. Phys. 57 (1985) 5325.CrossRefGoogle Scholar
  7. 7.
    S. Morita and K. Toda, ibid. 55 (1984) 2733.CrossRefGoogle Scholar
  8. 8.
    K. Toda and S. Yoshida, ibid. 63 (1988) 1580.CrossRefGoogle Scholar
  9. 9.
    Idem, Appl. Phys. 65 (1989) 857.CrossRefGoogle Scholar
  10. 10.
    S. Yoshida and K. Toda, Appl. Optics 29 (1990) 1793.CrossRefGoogle Scholar
  11. 11.
    K. Toda, S. Yoshida and H. Ikenaga, J. Mater. Sci. Lett. 12 (1993) 478.CrossRefGoogle Scholar
  12. 12.
    K. Ozawa, N. Takagi, K. Hiranaka, S. Yanagisawa and K. Asama, Jpn J. Appl. Phys. Suppl. 22-1 (1983) 457.CrossRefGoogle Scholar
  13. 13.
    N. Yukami, M. Ikeda, Y. Harada, M. Nisitani and T. Nishikura, IEEE Trans. Electron Devices ED-33 (1986) 520.CrossRefGoogle Scholar
  14. 14.
    R. Shukla, P. Khurana and K. K. Srivastava, Philos. Mag. B64 (1991) 389.CrossRefGoogle Scholar
  15. 15.
    M. M. Abdul-Gader, K. A. Wishah, Y. A. Mahmud, K. Toda and R. N. Ahmad-Bitar, Appl. Phys. A49 (1989) 665.CrossRefGoogle Scholar
  16. 16.
    M. M. Abdul-Gader and K. A. Wishah, J. Mater. Sci., in preparation.Google Scholar
  17. 17.
    G. Frigerio and C. Paracchini, Solid State Commun. 55 (1985) 625.CrossRefGoogle Scholar
  18. 18.
    S. S. Simeonov, E. I. Kafedjiiska and A. L. Guerassimov, Phys. Status Solidi(a) 136 (1993) 393.CrossRefGoogle Scholar
  19. 19.
    J. G. Simmons, in “Hand Book on Thin Film Technology” ch. 14, edited by L. I. Maissel and R. Glang (McGraw-Hill, New York, 1970).Google Scholar
  20. 20.
    S. M. Sze, “Physics of Semiconductor Devices” (Wiley, New York, 1981).Google Scholar
  21. 21.
    M. Shur, “Physics of Semiconductor Devices” (Prentice-Hall, Englewood Cliffs, NJ, 1990).Google Scholar
  22. 22.
    N. F. Mott and E. A. Davies, “Electronic Processes in Non-Crystalline Materials” (Clarendon, Oxford, 1979).Google Scholar
  23. 23.
    D. R. Lamb, “Electrical Conduction Mechanisms in Thin Insulating Films” (Methuen, London, 1967).Google Scholar
  24. 24.
    M. A. Lampert and P. Mark, “Current Injection in Solids” (Academic Press, New York, London, 1970).Google Scholar
  25. 25.
    D. Carles, C. Vautier and C. Viger, Thin Solid Films 17 (1973) 67.CrossRefGoogle Scholar
  26. 26.
    S. Antohe, Phys. Status Solidi(a) 136 (1993) 401.CrossRefGoogle Scholar
  27. 27.
    V. E. Baranyuk and V. P. Makhnil, Sov. Phys. Semicond. 25 (1991) 130.Google Scholar
  28. 28.
    A. G. Milnes, “Deep Impurities in Semiconductors” (Wiley, New York, 1973).Google Scholar
  29. 29.
    S. Hava, J. Appl. Phys. 59 (1986) 4097.CrossRefGoogle Scholar
  30. 30.
    S. Ozdemir and O. Oktu, J. Non-Cryst. Solids 107 (1989) 289.CrossRefGoogle Scholar
  31. 31.
    M. Hack, S. Guha and M. Shur, Phys. Rev. B30 (1984) 6991.CrossRefGoogle Scholar
  32. 32.
    R. H. Bube, “Photoconductivity in solids” (Wiley, New York, 1960).Google Scholar
  33. 33.
    A. Rose, “Photoconductivity and Related Processes” (Interscience, New York, 1963).Google Scholar
  34. 34.
    S. M. Pyvkin, “Photoelectric Effects in Semiconductors” (Consultants Bureau, New York, 1964).Google Scholar
  35. 35.
    P. Gorlich, “Photoconductivity in Solids” (Dover, New York, 1967).Google Scholar
  36. 36.
    J. Mort and D. M. Pai (eds), “Photoconductivity and Related Phenomena” (Elsevier, Amsterdam, New York, 1976).Google Scholar
  37. 37.
    C. Kittel, “Introduction to Solid State Physics”, 4th Edn (Wiley, Chichester, 1971).Google Scholar
  38. 38.
    D. Carles, G. Lefrancois and J. P. Larmagnac, J. Phys. Lett. (Paris) 45 (1984) L901.CrossRefGoogle Scholar
  39. 39.
    J. Grenet, D. Carels, G. Lefrancois and J. P. Larmagnae, J. Non-Cryst. Solids 56 (1983) 285.CrossRefGoogle Scholar
  40. 40.
    S. El-Halawany, R. Bacewiz, J. Filipowicz and R. Trykozko, Phys. Status Solidi A84 (1984) K89.CrossRefGoogle Scholar
  41. 41.
    Z. El Charras, B. Bourahla and C. Vautier, J. Non-Cryst. Solids 155 (1993) 171.CrossRefGoogle Scholar
  42. 42.
    M. F. Kotkata, M. Fustoss-Wegner, L. Toth, G. Zentai and S. A. Nouh, Appl. Phys(J. Phys. D.) 26 (1993) 456.CrossRefGoogle Scholar
  43. 43.
    V. Halpern, J. Phys. C 21 (1988) 2555.CrossRefGoogle Scholar
  44. 44.
    M. Gailberger and H. Bassler, Phys. Rev. B44 (1991) 8643.CrossRefGoogle Scholar

Copyright information

© Chapman and Hall 1997

Authors and Affiliations

    • 1
  1. 1.Department of PhysicsUniversity of JordanAmmanJordan

Personalised recommendations