*Thin Films Processed by SILAR Method DOI: http://dx.doi.org/10.5772/intechopen.106476*



*A list of materials deposited using SILAR technique with their growth conditions. (C, a: Cationic, anionic).*

expected phase on the substrate surface. The other oxides such as Ag3VO4 [36], BiVO4 [37, 68], Cu2V2O7 [35], and Fe2V4O13 [38] follow similar trends. Though bismuth oxyhalides, for instance, BiOI [69, 70] is not a pure oxide but have been synthesized by the SILAR using cationic precursor of bismuth nitrate and anionic precursor of KI [71].

## **3.2 Metal sulfides**

The characteristic easiness of the procedure and wide-ranging obtainability of the anionic precursors afford metal sulfides the most fabricated materials by employing SILAR technique. The easiest way of sulfide thin film deposition is to use metal salts as cationic precursors and H2O-soluble sodium sulfides or thiosulfates as anionic precursors. For example, NiS thin films could be fabricated using NiSO4 (pH: 8) as cationic precursors and Na2S (pH: 10) as anionic precursors even at room temperature [47]. Generally, the solubility product constants of used sulfide materials in water are higher than 1020, for instance, CuS: ≈10<sup>36</sup> and CdS: ≈1027, which is the key force of the deposition of the expected metal sulfides. Among the sulfides, CuS [72], ZnS [43, 73], CdS [46], Ag2S [44, 45], SnS [48], and PbS [49] have been broadly investigated mostly depending on the usage of chlorides and nitrates as the metal precursors and Na2S as anionic precursors for the S2 source. Moreover, the investigation on NiS [47], Bi2S3 [52] and MoS2 [13, 50], As2S3 [13, 51], MnS [53] are growing fast, while in the case of CoS [57], La2S3 [58] studies are still infrequent. Moreover, core@shell-like SnS2@Co3S4, ternary (NiCo2S4), and quaternary (Cu2BaSnS4) films as well as nanocomposites of CdS and Bi2S3 have been reported with their potential applications.

#### **3.3 Metal selenides**

In most of the cases, SILAR fabrication of the metal selenides has been directed through a solution of chloride, nitrate, or sulfate functioned as cationic precursor consisting of the anticipated metal, and a solution of Na2SeSO3 worked as the anionic precursor consisting of the source of Se<sup>2</sup> to form selenides. For example, 0.2 M CdCl2. H2O (pH: 8) reacts with 0.1 M Na2SeSO3 (pH: 11.3) to fabricate CdSe thin film [61]. Based on requirements, sometimes NaHSe, ethanolic NaBH4, or Na2Se can also be used as an anionic precursor to fabricate metal selenides. The SILAR deposition of Cu3Se2, Sb2Se3, Bi2Se3, and CdSe were studied and investigated mainly at room temperature avoiding thermal treatment during the sample growth, which was always maintained at (70–90) <sup>0</sup> C in the traditional cases.
