Photosensors-based on cadmium sulfide (CdS) nanostructures: a review

Abstract

Cadmium sulfide (CdS) is an II-VI semiconductor with a direct bandgap of 2.4 eV; it has been used for various applications, such as nonlinear optical devices, flat-panel displays, light-emitting diodes, lasers, logic gates, transistors, photoresistors, solar cells, infrared waveguides, and splitters. CdS nanostructures have been synthesized through two different routes: (1) vapor-phase growth and (2) liquid-phase growth. The vapor-phase growth system can yield highly pure single-crystal nanostructures, and liquid-phase growth has been carried out through chemical or electrochemical reactions in solution with templates. The fabricated nanostructures of CdS showed a relatively low work function, high refractive index, excellent transport properties, good chemical capability, thermal stability, high electronic mobility, and piezoelectric properties. For these reasons, CdS photosensors have been produced using various nanostructures of CdS, such as nanorods, nanoribbons, and nanowires. For the fabrication of CdS nanowire photosensors, many different approaches have been demonstrated to connect nanostructures in devices and circuits using various techniques, such as dry transfer, wet transfer, and contact printing. Each method has practical advantages and drawbacks in the implementation of nanostructures in devices. In this article, the synthesis of CdS nanostructures and the fabrication of photosensors based on the CdS nanostructures are reviewed.