Band gap tailoring of chemically synthesized lead sulfide thin films by in situ Sn doping

Abstract

In the present report, undoped and tin (Sn)-doped lead sulfide thin films were synthesized via chemical bath deposition method. The effects of Sn molar concentration on the optical, structural, and morphological properties were systematically studied. The concentration of Sn in the chemical bath was characterized by the ratio of [Sn +2 ]/[Pb +2 ] and varied from 0 to 15 at.%. Both doped and undoped thin films were polycrystalline in nature with a face-centered cubic crystal structure; however, the preferred orientations of the crystallites were varied along the (111) and (200) planes with Sn-doping concentration. The X-ray powder diffraction results also showed that peak intensities and the crystalline size were decreased with increasing Sn concentration.The lattice constant varied with Sn concentration and found in the range of 6.020 to 5.944 Å. The variation of Sn concentration in PbS:Sn thin films were confirmed by energy dispersive X-ray analyses study. The scanning electron microscope and atomic force microscopy studies revealed that Sn doping had a critical role on the surface roughness and morphology of the PbS:Sn thin films. The optical band gap study showed that the band gap of PbS:Sn thin films were engineered from 0.676 to 1.345 eV because of incorporation of Sn +2 ions via cost-effective chemical route.Room temperature photoluminescence spectra showed a well-defined peak at 427 nm and shoulders at 405 and 462 nm for all Sn-doped and undoped PbS samples.

Synthesis and characterization of PbS nanowires doped with Tb3+ ions by using chemical bath deposition method

“…Among them, one-dimensional semiconductor phosphor nanocrystal structures have been extensively studied for the last two decades because of their unusual structural, electronic, and optical properties [3]. Lead sulfide (PbS) is among the IV-VI group semiconducting material with direct band gap of 0.41 eV at room temperature and a space group of Fm3m [4]. Moreover, its absorption coefficient continuously increases from the infrared to the visible region [5].…”

Chemically deposited Sn-doped PbS thin films for infrared photodetector applications

“…This could be due to the decreased film thickness with an increase in Sn salt concentration in the solution (Table 1). Hone et al [17] also observed the decreased grain size of PbS films with increased Sn-doping concentration. For the better physical and chemical properties of the PbS, the crystalline growth should be uniform.…”

“…Doping is an effective technique to modify the optical, electrical and structural properties of the semiconductor materials. As reported, doping of certain rare earth elements and transition metals can alter the optical band gap, the carrier density and the electrical resistivity of PbS thin films [16,17]. Several research groups have tested different dopant elements such as Ag, Al, Cu, Cd, Zn, Sb, Sn, etc.…”

“…Further, the closer ionic radius of Sn 2+ does not cause much lattice strain in PbS after doping. A few studies have reported the growth of Sn-doped PbS thin films by CBD [17,24] and spray pyrolysis [28]. These studies reported the decreased grain size, increased band gap energy of PbS films with increased Sn-doping concentration.…”

Determining the majority charge carrier, optical and structural properties of electrochemically deposited lead tin sulfide (PbSnS) thin films

“…Numerous methods such as spray pyrolysis [9], thermal evaporation [8], hot wall vacuum deposition [10], hot-wall epitaxy [11], chemical bath deposition [2,12,13] and successive ionic layer adsorption and reaction (SILAR) [14], have been used to synthesize PbSnS. However, there are relatively very few publications on the deposition of the ternary PbSnS by electrochemical deposition.…”