Структурные и электрофизические свойства пленок PbS, легированных Cr-=SUP=-3+-=/SUP=- в процессе химического осаждения

Abstract

The evolution of the morphology, composition, structural characteristics (lattice constant, microstrains, texturing), optical and photoelectric properties of the PbS films obtained by chemical bath deposition in the presence of ammonium iodide and chromium (III) chloride at a concentration of up to 0.02 M has been studied. According to the elemental analysis by an energy dispersive X-ray spectroscopy, the chromium content in the PbS films has a nonmonotonic dependence on the CrCl3 concentration, and the largest amount is 1.08 at%. The particle size distribution is monomodal, and the average size of the particles forming the films varies from ~ 100 to ~ 225 nm with a content of 2–6% of nanoparticles. The introduction of NH4I and CrCl3 into the reactor preserves the cubic B1 structure of lead sulfide and results in an increase in the band gap Eg by 0.16–0.20 eV, a decrease in the dark resistance Rd, and an increase in the voltage sensitivity Us. The dependences of Eg and Us on the concentration of the chromium salt in the reaction bath have an extreme character with a maximum at 0.016 M, which is associated with the nonmonotonic incorporation of chromium into the PbS lattice. The results of studying the current-voltage characteristics of thin-film PbS(I) and PbS(I, Cr) layers are in good agreement with the results of the structural, optical, and photosensitive properties.