Haldar, Arpita and Bera, Susanta and Jana, Sunirmal and Bhattacharya, Kallol and Chakraborty, Rajib (2014) Development of a cost effective surface-patterned transparent conductive coating as top-contact of light emitting diodes. Journal of Applied Physics, 115 (19). ISSN 0021-8979

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Sol-gel process has been used to form indium zinc oxide films using an optimized combination of zinc to indium concentration in the precursor solutions. Different structures, like one (1D) and two-dimensional (2D) gratings and diffractive optical elements (DOEs) in the form of Fresnel lens are fabricated on the film surface of proposed top metal contact of LED by imprint soft lithography technique. These structures can enhance the LED's light extraction efficiency (LEE) or can shape the output beam pattern, respectively. Several characterizations are done to analyze the material and structural properties of the films. The presence of 1D and 2D gratings as well as DOEs is confirmed from field emission scanning electron and atomic force microscopes analyses. Although, X-ray diffraction shows amorphous nature of the film, but transmission electron microscopy study shows that it is nano crystalline in nature having fine particles (similar to 8 nm) of hexagonal ZnO. Shrinkage behaviour of gratings as a function of curing temperature is explained by Fourier transform infra-red spectra and thermo gravimetric-differential thermal analysis. The visible transmission and sheet resistance of the sample are found comparable to tin doped indium oxide (ITO). Therefore, the film can compete as low cost substitute of ITO as top metal contact of LEDs. (C) 2014 AIP Publishing LLC.

Item Type: Article
Subjects: Electronics
Divisions: Sol Gel
Depositing User: Bidhan Chaudhuri
Date Deposited: 03 Dec 2014 11:14
Last Modified: 03 Dec 2014 11:14
URI: http://cgcri.csircentral.net/id/eprint/2589

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