Magnetic field influenced growth kinetics in chemical CdS thin-film deposition

The kinetics of growth for the deposition of CdS thin films from chemical solutions has been studied without and under the action of an external magnetic field. It has been established that the growth takes place out of a narrow near-surface transition layer between liquid and solid, where mobile ions are moved by the field, resulting in thin, adherent and specularly reflecting films. The presence of an external magnetic field affects the formation process of the CdS films in a characteristic manner, and allows to control thickness, grain size and optical quality of the grown layers. Optical transmission spectroscopy measurements reveal, that the band gap energy of 2.36 eV for films grown without the application of a magnetic field, increases to 2.51 eV for the highest field strength applied. The film thickness under otherwise identical conditions increases by about a factor of 3, while the medium grain size shrinks to almost half the value of about 70 nm found without external field action. AFM images are applied in the study, showing an improved smoothness of the films.