Investigations of inorganic-organic hybrid photodetector

Abstract

Metal oxide nanostructures have been utilized as suitable candidates for optoelectronic applications as they are chemically and thermally stable, provide larger surface to volume ratio for better interaction with their environment. Among them, ZnO is attractive material because of its capability of showing morphological diversity. Different nanostructures with varying aspect ratios, morphology have been investigated. In this work, ZnO Nanostructures (ZNS) were synthesized over ITO coated glass substrate by hydrothermal technique using Zinc nitrate and Hexamethylenetetramine solution with in situ addition of Potassium Permanganate (KMnO₄). On varying the precursor concentrations during hydrothermal growth, change in morphological structures from Nanorods to Nanopencils and Nanoplates have been observed. It is demonstrated that the KMnO4 concentration has great influence on morphology and on the alignment of ZnO Nanostructures. Effect of KMnO4 on the optoelectronic properties of the grown nanostructures has also been analyzed. High aspect ratio is desired as material properties depend closely on it, thus, ordered Nanostructures are expected to enhance performance of various technologically important devices like Light emitting diodes, Solar cells, Biosensors and Photodetectors. The Bilayered Hybrid detector consisted of ZNS coated with a layer of π-conjugated polymer viz. MDMO-PPV. The working device is sensitive towards visible spectrum of light (λ=490nm). The detailed mechanism of growth of ZNS along with its overall influence on response of resulting Hybrid Photodetector will be discussed in detail in our work. The highlight of the work is enhanced performance of our ZnO/MDMO-PPV hybrid device with a significantlyhigh rectification ratio of 466, highest photosensitivity obtained around 6923 and Photoresponsivity of 3.7A/W at -12V under an incident light with wavelength 490 nm.