Temperature and Deposition Time Effect on Properties and Kinetics of CdSe and CdS0.25Se0.75 Films Deposited by CBD

Abstract

CdSe and CdS 0.25 Se 0.75 thin films were grown by the Chemical Bath Deposition technique at different temperatures (50-90°C) and deposition times (5-180 min). Both kinds of films are polycrystalline, constituted by nanostructured clusters of particles. CdSe films consist in a mixture of cubic and hexagonal phases (4-8 nm crystal size), whereas only the hexagonal phase is observed in the CdS 0.25 Se 0.75 ones (6±1 nm crystal size). A decrease on the CdSe films density was observed due to the sulfur introduction into the crystal lattice. The composition of the ternary films is affected by both temperature and deposition time. The Band gap values (E g ) are affected by temperature, atomic composition and deposition time, decreasing from 2.09 to 1.93 eV, showing a quantum confinement effect mainly in the CdSe films. The films thickness, ranging from 30 to 600 nm, increases as a function of temperature and deposition time. Photoluminiscence signal is improved after thermal treatment, evidenced by the radiative broad bands observed at 1.84 and 2.20 eV.

Characterization of Thermally Evaporated CdSe1-XSX Thin Films for Solar Cells Applications

“…Electrical and optical properties of semiconducting thin films are vital requirements for appropriate applications in several optoelectronic devices [11,12]. Modifying the composition of the ternary CdSe1-xSx thin films permits improvement of electrical, optical and structural properties of the binary CdSe thin films, therefore; widening of its scientific and technological applications [13]. Nano-sized CdSe1-xSx thin films can be prepared by several chemical and physical methods such as chemical bath deposition (CBD), chemical vapor deposition (CVD), RF-sputtering, spray pyrolysis, laser ablation and thermal evaporation techniques [13][14][15][16].…”