Chemically deposited CdS films in an ammonia-free cadmium–sodium citrate system

Detailed Analysis of Five Aspects Addressed to Minimize Costs and Waste in the Chemical Bath Deposition of CdS Films Using the Cd<i>B</i>–<i>A</i>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>–<i>A</i>OH–(NH<sub>2</sub>)<sub>2</sub>CS System

“…As mentioned in the previous section, this CdCl 2 concentration results in CdS films that are destroyed with the damp cotton after 20 min of immersion, an observation similar to that reported by Ortuño-López et al [56] and Ochoa-Landín et al [60] when they used 10.0 mL of 0.05 M CdCl 2 . To corroborate if the effect of a specific pH value of the reaction solution is the cause of this poor quality of the films, we synthesized and characterized four sets of CdS thin films in which, by using 12.0 mL of 0.05 M CdCl 2 and no pH 10 borate buffer, the KOH concentration and the immersion time were varied, and the results are presented in Figure 3, in which it is first evident that the thin film growth rate increases by increasing the pH.…”

“…Third, as the amount of CdCl 2 was increased, maintaining constant the immersion time, the log(T -1 ) values also increased. According with that discussed with Equation (2), this is directly related to the increase in thin film d. This increase in the growth rate by increasing the Cd 2+ ions amount is widely supported by the literature [56,60,[77][78][79][80][81][82][83][84][85][86]. Fourth, as reported by Ochoa-Landín et al [60], there is a slight difference between the films deposited in a reaction solution containing pH 10 borate buffer, compared with those deposited in the absence of the buffer.…”

“…They synthesized four sets of CdS thin films within the parameters of temperature, reagent concentration, and immersion time that were used in the work reported by Ortuño-López et al [56], but with the difference that no buffer was added to the reaction solutions. Then, they compared their results with those reported by Ortuño-López et al five years ago [56], finding only minor differences, which provided arguments for their discussion.…”

“…They synthesized four sets of CdS thin films within the parameters of temperature, reagent concentration, and immersion time that were used in the work reported by Ortuño-López et al [56], but with the difference that no buffer was added to the reaction solutions. Then, they compared their results with those reported by Ortuño-López et al five years ago [56], finding only minor differences, which provided arguments for their discussion. A critical comparison between the two mentioned publications clarifies the high similarity of the general properties of CdS thin films deposited with and without pH 10 borate buffer, despite that they were made by different persons and probably with different batch reagents, but maintaining unchanged the rest of the conditions specified in the Ortuño-López-2004 formulation.…”

“…In addition, in 2004 Ortuño-López et al reported another work [56] in which they succeeded in obtaining of CdS thin films using low concentrations of all the reagents, being able to use even the half of the concentrations used in the original ammonia-free citrate-containing formulation. Then, although with small variations in the concentrations of the reagents, this less-harmful formulation began to be widely used by research groups in Mexico and USA [4,[56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71], and in other countries [72][73][74]. their effects.…”