Optical and structural properties of nanocrystalline PbS thin film grown by CBD on Si(1 0 0) substrate

Abstract

PbS nanocrystalline thin film was prepared by chemical bath deposition on Si(1 0 0) substrate at bath temperatures of 25, 45 and 65 °C. Triethanolamine was added to the aqueous solution, which decreased the grain size and increased the luminescence of the nanocrystalline PbS thin film. PbS nanocrystals were identified using XRD, TEM and AFM. The crystalline size of the PbS film deposited at different bath temperatures was estimated by XRD and TEM to be 7–12 nm. The growth mechanism of the PbS crystallites were described at different bath temperatures. The confinement was reflected in the absorption spectra, photoluminescence excitation and photoluminescence spectra. The luminescence of Si(1 0 0) substrate and PbS nanocrystalline film deposited on Si(1 0 0) were compared, and the results revealed that the PbS nanocrystals altered and notably enhanced the emission features of the Si(1 0 0) substrate. The shifting of the maximum photoluminescence emission wavelength of PbS nanocrystals with a change in bath temperature and the variation in photoluminescent intensity of PbS nanocrystals prepared at 25 °C versus deposition time were investigated. A single-peak fit of a Gaussian function was employed to discern the photoluminescence of PbS on Si(1 0 0) substrate.

Keywords:

• nanocrystalline PbS
• photoluminescence
• chemical bath deposition