Morphological and optical study of thin films of CuAlS₂deposited by metal organic chemical vapour deposition technique

Bridging the p-type transparent conductive materials gap: synthesis approaches for disperse valence band materials

“…25,33 Thin films of CuAlS 2 have been applied as a transparent p-type contacts in CIGS and organic solar cells, 33,92 but the material has otherwise received relatively limited attention in the literature. Despite the smaller number of studies, CuAlS 2 has been synthesized by a wide variety of deposition techniques, including solution-based techniques, such as CBD, 33,93 CVD methods, such as atomic layer deposition (ALD) and MOCVD, 91,92,94 solid-state synthesis routes, 25 thermal evaporation or sulfurization, [95][96][97][98] and even spray pyrolysis. 99,100 One important finding from these investigations is Cu-rich composition leading to higher conductivity, 26,33 due in part to the VB shifting upward with increasing copper content.…”

“…As with any sulfide, experimental challenges to synthesizing CuAlS 2 or Cu-alloyed ZnS thin films arise mostly related to sulfur management, in particular the need to avoid toxicity from hydrogen sulfide (H 2 S). This is the case in any vacuum-based method, CVD-based deposition, or thermal evaporation, as precursors used to deliver sulfur to the growing film typically lead to unintentional formation (or incomplete utilization) of H 2 S. 91,92 For this reason, solution-based methods are more attractive since sulfur-containing reagents can be more readily controlled. However, CBD can lead to inhomogeneity in the resulting film, 33 and often such films require postdeposition annealing to obtain good crystallinity and the desired TCM properties, which leads again to the issues of sulfur management.…”

Morphology and optical properties of CuAlS₂ crystals prepared using the solid-phase Al and S precursors

“…Preparation of the intermediate complex had been reported previously by Damisa et al (2017) by modifying the method of Ajayi et al (1994). This was followed by coupling of the intermediate complex to prepare the various precursors.…”

“…In our previous study (Damisa et al 2017), we established that the growth of CuAlS2 from a single source precursor using the MOCVD technique is achievable. However, we observed from literature that the growth of CuAlS2 in thin-film form proceeds via two or more precursors where a stable film of CuAlS2 was not achieved (Miyake et al 1995, Benchouck et al 1999).…”

“…These solid source precursors are novel to the best of our knowledge and are scarcely reported in the literature. The MOCVD technique used in this study had been previously used to synthesize binary and ternary oxides (Ajayi et al 1994, Adedeji et al 2002 and sulphide films (Osasona et al 1997, Eleruja et al 1998, Damisa et al 2017.…”