Low temperature anisotropic photoresponse study of bulk ZrS3 single crystal

Abstract

The present work shows zirconium trisulphide (ZrS3) single crystals-based photodetector functionality synthesized through the Direct Vapor Transport (DVT) technique. The elemental-chemical, surface morphology, structural phase, crystallinity and vibrational modes of the crystals were analyzed using Energy Dispersive Analysis of X-rays (EDAX), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Raman Spectroscopy respectively. These characterizations revealed the pure and layered crystals grown having a monoclinic phase with good crystallinity. Time-dependent photo-response of the detector fabricated from ZrS3 single crystals possessing smooth surface was recorded under the illumination of white light for different incident illumination levels (20 mW/cm2 to 120 mW/cm2) at room temperature. Further, a low-temperature photo-response upto 100 K for the incident light intensity of 120 mW/cm2 was carried out to validate the stability and durability of the detector. Typical detector parameters like responsivity, detectivity, sensitivity and response times were calculated and their variations are studied thoroughly concerning incident intensity and low-temperature. Furthermore, owing to the layered structure of the material, the photo-response of the device was recorded in both parallel (⊥to c-axis) and perpendicular (║to c-axis) direction of the crystallographic b-axis and device parameters were calculated at the room as well as low temperatures. The device exhibited strong anisotropy that originated from the layered structure of the grown crystals and involved an anisotropic charge conduction mechanism at the room as well as low temperatures.