Effect of pre-annealing on the structural evolution and optical response of Ag films exposed to iodine vapours

  • R Praveena
  • V Sravani Sameera
  • N V Prabhakara Rao Thirumala
  • C S Sunandana
  • M Ghanashyam KrishnaEmail author


Ag thin films of 5 nm thickness were deposited on glass substrates by thermal evaporation. The films were divided into two sets, out of which, one set was not annealed and the other set was subjected to pre-annealing at \(300^{\circ }\hbox {C}\) for 2 h in air. The un-annealed and pre-annealed films were exposed to iodine vapours at room temperature for the durations from 5 min to 10 h. The un-annealed films were crystallized into the \({\upbeta }\) phase of AgI after exposure for 5 h. In contrast, for the pre-annealed films, crystallization into the \({\upbeta }\) phase occurred within the first 5 min. Both sets of films, however, exhibit a strong preferential c-axis orientation in the \({\upbeta }\)-AgI phase. Optical absorption studies reveal that the un-annealed films exhibit a localized surface plasmon resonance (LSPR) with a peak at 545 nm and a long wavelength shoulder at 620 nm, which shifts to 516 nm after iodization for a few minutes. This peak position does not change with further iodization. The LSPR for the pre-annealed films has a single peak at 538 nm. After iodization for a few minutes, this peak shifts to 525 nm. Iodization for 3 h results in a further blue-shift of this resonance to 475 nm. The photoluminescence spectrum reveals two peaks, one at 368 nm and the other at 712 nm. The first one is assigned to the excitons of AgI, whereas the long wavelength peak is attributed to the presence of disorder in the films. The reasons for the difference in behaviour of the un-annealed and pre-annealed films are discussed.


AgI thin films iodization annealing effects 



One of the authors (RP) is grateful to the DST, Govt. of India, for the award of Major Research Project (No. SR/S2/CMP-96/2012). We also acknowledge facilities provided by the Centre for Nanotechnology, School of Chemistry and School of Physics, University of Hyderabad.


  1. 1.
    Burnley G 1963 Am. Mineralog. 48 1266Google Scholar
  2. 2.
    Eachus R S, Marchetti A P and Muenter A A 1999 Annu. Rev. Phys. Chem. 50 117CrossRefGoogle Scholar
  3. 3.
    Guo X, Zheng G and Jin D 2006 Atm. Res. 79 183CrossRefGoogle Scholar
  4. 4.
    Sunandana C S 2013 Indian J. Pure Appl. Phys. 51 296Google Scholar
  5. 5.
    Chen Z, Wang W, Zhang Z and Fang X 2013 J. Phys. Chem. C 117 19346CrossRefGoogle Scholar
  6. 6.
    Tappertzhofen S, Valov I and Waser R 2012 Nanotechnology 23 145703CrossRefGoogle Scholar
  7. 7.
    Liang X F, Chen Y, Shi L, Lin J, Yin J and Liu Z G 2007 J. Phys. D: Appl. Phys. 40 4767CrossRefGoogle Scholar
  8. 8.
    George R and Harrington J A 2005 Appl. Opt. 44 6449CrossRefGoogle Scholar
  9. 9.
    Sui K, Shi Y, Tang X, Zhu X, Iwai K and Miyagi M 2008 Opt. Lett. 33 318CrossRefGoogle Scholar
  10. 10.
    Bledt C M, Harrington J A and Kriesel J M 2012 Appl. Opt. 51 3114CrossRefGoogle Scholar
  11. 11.
    Kumar P S, Dayal P B and Sunandana C S 1999 Thin Solid Films 357 111CrossRefGoogle Scholar
  12. 12.
    Kumar P S, Ray S and Sunandana C S 2001 Mater. Phys. Mech. 4 39Google Scholar
  13. 13.
    Kumar P S and Sunandana C S 2002 Nano Lett. 2 975CrossRefGoogle Scholar
  14. 14.
    Mohan D B, Sreejith K and Sunandana C S 2007 Appl. Phys. B 89 59CrossRefGoogle Scholar
  15. 15.
    Mohan D B and Sunandana C S 2006 J. Appl. Phys. 100 064314CrossRefGoogle Scholar
  16. 16.
    Gnanavel M, Mohan D B and Sunandana C S 2008 Thin Solid Films 517 1058CrossRefGoogle Scholar
  17. 17.
    Rajesh D and Sunandana C S 2012 Thin Solid Films 524 316CrossRefGoogle Scholar
  18. 18.
    Muhammad Y B, Talebi R, Kassar T, Nahal A, Ristein J, Unruh T et al 2016 Sci. Rep. 6 21439CrossRefGoogle Scholar
  19. 19.
    Ghosh S, Saraswathi A, Indi S S, Hoti S L and Vasan H N 2012 Langmuir 28 8550CrossRefGoogle Scholar
  20. 20.
    Mochizuki S and Umezawa K 1997 Phys. Lett. A 228 111CrossRefGoogle Scholar
  21. 21.
    Shirin S and Aziz H 2015 Mater. Sci. Semicond. Proc. 34 74CrossRefGoogle Scholar
  22. 22.
    Choi J, Reddy D A and Kim T K 2015 Ceram. Int. 41 13793CrossRefGoogle Scholar
  23. 23.
    Liang C, Terabe K, Tsuruoka T, Osada M, Hasegawa T and Aono M 2007 Adv. Funct. Mater. 17 1466CrossRefGoogle Scholar
  24. 24.
    Cazzanelli E, Fontana A, Mariotto G, Rocca F, Mazzacurati V, Ruocco G et al 1988 Phys. Rev. B 38 10883CrossRefGoogle Scholar
  25. 25.
    Malinsky M D, Kelly K L, Schatz G C and van Duyne R P 2001 J. Am. Chem. Soc. 123 1471CrossRefGoogle Scholar
  26. 26.
    Noguez C 2007 J. Phys. Chem. C 111 3806CrossRefGoogle Scholar
  27. 27.
    Amendola V, Bakr O M and Stellacci F 2010 Plasmonics 5 85CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 2018

Authors and Affiliations

  1. 1.Department of PhysicsG.V.P. College of EngineeringVisakhapatnamIndia
  2. 2.School of PhysicsUniversity of HyderabadHyderabadIndia

Personalised recommendations