Please use this identifier to cite or link to this item: http://idr.nitk.ac.in/jspui/handle/123456789/12450
Title: Optoelectronic properties of hybrid diodes based on vanadyl-phthalocyanine and zinc oxide
Authors: Kiran, M.R.
Ulla, H.
Satyanarayan, M.N.
Umesh, G.
Issue Date: 2017
Citation: Superlattices and Microstructures, 2017, Vol.112, , pp.654-664
Abstract: We report an investigation of the optoelectronic properties of a hybrid p-n diode device fabricated using ZnO film prepared by sol-gel technique on which a VOPc organic film is deposited by vacuum evaporation. The charge transport properties of devices having the configurations ITO/ZnO/Al and ITO/ZnO/VOPc/MoO3/Al were investigated at different annealing temperatures (150 C, 250 C, 350 C and 450 C) by Impedance Spectroscopy (IS). The structural, morphological, optical and electrical properties were also studied at different annealing temperatures. The parameters related to the ITO/ZnO and ZnO/VOPc interfaces such as ideality factor (n), barrier height (q?B) and rectification ratio (RR) of the diodes were determined from current density-voltage (J-V) characteristics. IS measurements suggest that the large photocurrent generated is due to the decrease in bulk resistance of the device on account of the generation of electron-hole pairs in the organic active layer when exposed to light. The RR and the photocurrent responsivity (Rph) values obtained from the J-V characteristics compare well with those obtained from the IS measurements. It was observed that the absolute value of Rph (470 mA/W) for the p-n diode with ZnO annealed at 350 C is high compared to that of diodes with different ZnO annealing temperatures. These values also agree well with the values obtained for p-n diodes of other phthalocyanines. Our studies clearly demonstrate that a p-n diode with ZnO film annealed at 350 C exhibits much better optoelectronic characteristics on account of increased grain size, improved charge injection due to the reduction of barrier height and hence higher (up to 5 orders) charge carrier mobility. 2017 Elsevier Ltd
URI: http://idr.nitk.ac.in/jspui/handle/123456789/12450
Appears in Collections:1. Journal Articles

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