The pronounced role of impurity phases in the optical properties of Mn catalyzed ZnS nanostructures

Abstract

We report the effect of Mn self-doping in Mn catalyzed ZnS nanostructures grown via vapor liquid solid mechanism, which also resulted in the formation of additional impurity minority phases like ZnO and MnO 2 . The synthesized ZnS nanostructures were subsequently annealed in the range of 500 • C -700 • C in an inert environment to remove impurity phases and enhance the incorporation of dopant. Room temperature photoluminescence showed strong defect assisted luminescence. It was observed that green emission due to intrinsic defects of ZnS nanostructures was reduced in magnitude and Mn related orange/red luminescence increased in magnitude in nanostructures annealed at high temperature. The presence of impurity phases led to the observation of surface optical and interface phonon modes as observed in the Raman spectroscopy. Dielectric continuum and phonon confinement models were employed to determine the correlation lengths of the optical phonon modes. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. [http://dx

Fast-Response Metal–Semiconductor–Metal Junction Ultraviolet Photodetector Based on ZnS:Mn Nanorod Networks via a Cost-Effective Method

“…However, in the pure form, ZnS exhibits highly insulating behavior due to its low donor–accepter defect level and high crystal quality, and without doping, it is not suitable for device applications . The intentional incorporation of doped impurities is considered as a fundamental approach for tailoring the physical and chemical properties of a semiconductor material, leading to the design and fabrication of photodetector, electronic, optoelectronic, and spintronic devices of desired features and characteristics. − 1D fluorescent nanomaterials with large surface-to-volume ratios exhibit enhanced light sensitivity, photoluminescence (PL), and fast response due to quantum confinement effects, , which can be efficiently improved and tuned with impurity concentration levels. Intentional doping of transition metals can generate midgap states in the II–VI compound semiconductors, which are involved in the band gap tuning and photoionization transitions through radiative or nonradiative decay and can contribute to the improvement of the photoconduction process. − Particularly, Mn 2+ -doped ZnS nanomaterials are considered as important luminescent materials due to their ability to modify the energy band and generate luminescent centers of different energy levels, giving rise to various interesting properties and applications. , …”