Incorporation of colloidal Si nanoparticles into chemical bath solutions to synthesize nc-Si/CdS nanocomposite thin films

Colloidal silicon nanoparticles (nc-Si) with diameters below 10 nm, were synthesized by the laser ablation of solids in liquids technique by ablating a bulk Si target immersed in deionized water. The obtained suspension was diluted in deionized water at volume ratios of 1:16, 2:15 and 4:13 in order to have different concentrations of Si nanoparticles. Each colloidal suspension was used to prepare precursor solutions for chemical bath deposition of nc-Si/CdS nanocomposite thin films with different nc-Si contents. According to UV–Vis Results, nanocomposite films reached optical transmission values of 90–98% for wavelengths above 500 nm, while the pure CdS reached values near 65%. Furthermore, the band gap increases linearly with nc-Si volume ratio in the bath. Photoluminescence emissions shifted to lower energies as nc-Si volume ratio increased. A signal associated to nanocrystalline Si appeared at 600 nm for nanocomposite films. Structural characterization showed no significant changes for nc-Si containing samples. •The laser ablation in solids technique can be combined with chemical bath deposition to synthesize nanocomposite thin films.•Nanocomposite films are crystalline.•Visible light emission from silicon nanoparticles embedded in CdS can be obtained.