ZnxCd1-xS thin films: A study towards its application as a reliable photodetector

Abstract

A reliable and stable photodetector shows enormous potential applications in health monitoring, intelligent wearable devices, and biological sensing. The noble opto-electrical properties of cadmium sulfide (CdS) makes it a favorable semiconductor for opto-electrical devices. The properties of CdS thin film can further be enhanced by alloying it with zinc sulfide (ZnS) to form Zn<inf>x</inf>Cd<inf>1-x</inf>S compound semiconductor. Herein, a high performance, Zn<inf>x</inf>Cd<inf>1-x</inf>S (x = 0, 0.15, 0.30, and 0.45) photodetector with good stability is designed and fabricated via a simple vacuum thermal evaporation technique. The various photodetector parameters of the Zn<inf>x</inf>Cd<inf>1-x</inf>S films were investigated as a function of its composition. Among the various compositions of the Zn<inf>x</inf>Cd<inf>1-x</inf>S thin films, the Zn<inf>0.15</inf>Cd<inf>0.85</inf>S films displayed excellent photosensitivity as high as 2.22 which is ~1.6 times higher than that of undoped CdS thin films. The research data suggests that a high-performance single layer Zn<inf>x</inf>Cd<inf>1-x</inf>S photodetector with good stability and reproducibility can be fabricated using a thermal evaporation technique. © 2019 Elsevier Ltd