Microwave-assisted chemical bath deposition of nanocrystalline CdS thin films with superior photodetection characteristics

• Nanocrystalline CdS films are fabricated via optimized MWCBD method.
• The quality of the CdS thin films depends on the concentration of TU.
• XRD, EDS, and PL analyses confirmed the formation of nanocrystalline CdS.
• The photodetector exhibited exceptional sensitivity of 952%.
• The photodetector showed a fast response time of 10 ms.

Nanocrystalline CdS thin films were grown on Si(1 0 0) substrates using microwave-assisted chemical bath deposition. Aqueous solutions of cadmium chloride (CdCl2) and thiourea (TU) were used as cadmium (Cd+2) and sulfur (S−2) ion sources, respectively. Structural, morphological, and optical analyses showed that the quality of the grown CdS nanocrystalline thin films depends on the concentration of TU. The photoresponse of the devices made using such CdS films strongly depends on the TU concentration. The photodetector made of CdS films synthesized using 0.15 M exhibited high responsivity and exceptional sensitivity of 952 at an applied voltage of 1 V. Upon exposure to 460 nm-light pulses, a fast response time (∼10 ms) was achieved. The obtained results revealed that the photoresponse properties of CdS-based photodetectors could be markedly improved by controlling the molar concentration of TU.

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