Wavelength dependent anisotropic photosensing activity of zirconium trisulfide crystal

According to the performance requirements, either bulk or nanocrystalline form of the material can be used for different types of device applications. In the present study, zirconium triselenide bulk crystals were grown by direct vapour transport technique. The energy-dispersive X-ray analysis (EDAX) confirms the purity of the grown crystals. The as-grown crystals and powder have been examined under Carl Zeiss optical microscope and scanning electron microscope (SEM) for morphological studies which revealed the evolution of crystalline phases of the material by the layered kind of growth mechanism. The transmission electron microscopy (TEM) with selected area electron diffraction (SAED) pattern analysis showed the grown crystals possess good crystallinity, whereas X-ray diffraction (XRD) analysis confirmed the monoclinic phase of the crystals. To study the effect of different wavelength sources (Blue-470 nm, Green-540 nm, Red-670 nm) on bulk zirconium trisulfide photodetectors, a pulse photo response experiment was carried out. The anisotropic behaviour is also revealed using the same sources. Various device parameters like responsivity, sensitivity, detectivity and external quantum efficiency (EQE%) were calculated. The highest responsivity and detectivity of 81.7 µA/W and 3.56 × 107 Jones were achieved for blue (470 nm) light source, respectively.