Hashim, Nur Hasyimah
(2019)
Study Of Metal Impregnated Zno Thin Film As Thermal Interface For High Power Led Applications.
Masters thesis, Universiti Sains Malaysia.
Abstract
Thermal issue in high power LEDs greatly impacts the performance of LED lighting in terms of its reliability and durability. Thermal interface materials have been recommended to improve heat dissipation as they are capable in conducting heat effectively between heat source and the heat sink. In this project, zinc oxide (ZnO) and two types metal impregnated ZnO (Copper and Silver) thin films were deposited on Aluminium substrates via sol-gel spin coating technique. The deposition parameters of ZnO thin films such as number of coating cycle and sol-gel concentration were varied to obtain good quality ZnO thin films. After the optimization of ZnO thin films, metal impregnated ZnO thin films were produced at concentration 0.03M, 0.06M, 0.09M. The structural properties of the thin films were investigate using XRD while surface morphology and topology of films were analysed through FESEM and AFM respectively. Thermal performance of the thin films were tested using T3Ster where high power LEDs mounted on coated substrates. X-ray diffraction results showed three major ZnO peak (100, 002, 101) with hexagonal crystal structure for all coated samples. Structural analysis of ZnO thin films showed the increment of crystallite size from 13.80 nm to 34.35 nm while FWHM reduced from 0.631º to 0.254º when number of coating cycles increased from 5 coating cycles to 20 coating cycles. However, as the ZnO concentration increased from 0.5M to 3.0M the crystallite size reduced from 34.35 nm to 29.04nm while FWHM increased from 0.254º to 0.301º. The intensity of ZnO peaks were decreased as both metal introduced into ZnO.
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