Thin Solid Films, Vol.517, No.20, 5943-5947, 2009
Optical properties and scanning probe microscopy study of some Ag - As -S - Se amorphous films
Doping of As-S-Se amorphous films by silver photo-dissolution leads to a decrease of the optical gap and to an increase of the refractive index in forming Ag-As-S-Se films. The difference of the optical gap and refractive index between undoped and doped films has been found in case of Ag(15)As(26)S(29)Se(30) film UP to 0.37 eV and 0.26, respectively. Transreflectance in far infrared spectral region indicates formation of AgAsS(2) and AgAsSe(2) entities in Ag(15)AS(26)S(29)Se(30) film. Scanning probe microscopy, namely atomic force microscopy, atomic force acoustic microscopy (AFAM) and Kelvin probe force microscopy (KPFM) was used for studying Ag-As-S-Se films. It was found that silver growth is rather three dimensional and it is reminiscent of the Stranski-Krastanov growth mode. Observed silver protuberances represent silver reservoirs responsible for a local increase of silver content. Hence, the silver growth mode enhances formation of nano/meso inhomogeneities of the surface and near surface density/stiffness, seen in AFAM, and in the surface electric potential, seen in KPFM. (C) 2009 Elsevier B.V. All rights reserved.
Keywords:Amorphous materials;Atomic force microscopy (AFM);Optical properties;Silver photodissolution