Preparation and formation mechanism of CdS nano-films via chemical bath deposition

Abstract

CdS semiconductor nano-films were grown on ITO glass substrates by means of chemical bath deposition (CBD), with Cd(NO₃)₂ as Cd ion and (NH₂)₂CS as S ion sources. The concentration of Cd ions, deposition temperature, deposition time and post-treatment temperature have an impact on the formation of CdS nano-films. UV-vis absorption spectrum and atomic force microscope (AFM) images indicated that the change of concentration and post-treatment temperature may adjust the band-gap of CdS to obtain stable, homogeneous and compact films. Formation mechanism of the crystal nucleus and CdS film was also discussed. Active sites on the surface of ITO are critical to the formation of the crystal nucleus and a uniform and compact CdS nano-film. The active site and crystal nucleus are formed due to the comprehensive effect of electricity, thermodynamics and chemistry.

References

1. Rao A P Pajonk G M Rao V Effect of pH, aging, and drying on the size of CdS nanocrystallites,monolithicity, and transparency of nanocrystalline CdS-Doped silicaxerogelsJ Mater Syn Proce 2001 91118
2. Vigil O Rodrìguez Y Zelaya-Angel O Vèzquez-Lòpez C Morales-Acevedo A Vèzquez-Luna J G Properties of CdS thin films chemicallydeposited in the presence of a magnetic fieldThin Solid Films 1998 322329333
3. Yamaguchi K Yoshida T Sugiura T Minoura H A novel approachfor CdS thin-film deposition: electrochemically induced atom-by-atomgrowth of CdS thin films from acidic chemical bathJ Phys Chem B 1998 10296779686
4. Ichimaura M Goto F Arai E Structural and optical characterization of CdS films grownby photochemical depositionJ Appl Phys 1999 8574117417
5. Lozada-Morales R Zelaya-Angel O Torres-Delgado G On the yellow-band emission in CdS filmsAppl Phys A 2001 736165
6. Oliva A I Solís-Canto O Castro-Rodríguez R Quintana P Formation of the band gap energy on CdS thin films growthby two different techniquesThin Solid Films 2001 3912835
7. Martínez M A Guillén C Herrero J Morphological and structural studies of CBD-CdS thin filmsby microscopy and diffraction techniquesAppl Surf Sci 1998 136816
8. Yang J Tian H Z Wang C X Fabrication of high-quality transparent ZnO/Diamond heterojunctionJournal of Jilin University (Science Edition) 2006 43460464(in Chineses)
9. Allen P B Cardona M Theory of the temperature dependenceof the direct gap of germaniumPhys RevB 1981 23414951505
10. Zhang H Yang D R Ma X Y Que D L CdS thin filmsfabricated by chemical bath depositionActaEnergiae Solaris Sinica 2003 24114(in Chineses)