Transparent and conductive thin films of cadmium doped tin oxide fabricated by pulsed laser deposition technique

Abstract

Transparent conducting thin films of cadmium doped tin oxide (CTO) were successfully fabricated on glass substrates by pulsed laser deposition technique. Several analytical tools were employed to explore the causes of changes in the structural, optical and electrical properties of these films as a function of doping concentration. The 3 wt % Cd doped films showed lowest electrical sheet resistance of 300.9Ω/□ with electrical resistivity of 2.407×10−3Ωcm. The CTO films are optically transparent with more than 80% transmission in the visible and near IR region of the electromagnetic spectrum. The optical energy gap of CTO films marginally varied from 3.40 eV to 3.49 eV for different doping amount. The AFM studies showed an increase in the surface smoothness of the film with Cd doping concentration. The X-ray diffraction study revealed the tetragonal structure of the film with lattice parameters a=4.742Å and c=3.177Å. The enhanced electrical conductivity and optical transmittance characteristics in these pulsed laser deposited Cd:SnO2 thin films, are suitable, for photo anode/electrode applications in solar cells and display panels.