Improvement Of Led Light Extraction Efficiency By Silica Micro Repeating Structure Growth
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Date
2018-08-01
Authors
Joshua Gan, Oon Joo
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Light extraction efficiency (LEE) is an important factor for Light Emitting
Diodes (LED). As of today, most LEE improvement methods involve complex
fabrication either on the finished LED chip or during the LED processing itself. In
this study, micro repeating structures (MRS) are constructed using silica micro
repeating structure growth (SMRSG) to improve LEE. In contrast to other complex
fabrication methods, the SMRSG was done through a Stöber solution growth
method. The solution preparation was relatively simple, using tetraethyl orthosilicate
(TEOS), surfactant and solvents. The LEE result of the LED after SMRSG was
characterized through using a spectrophotometer. It showed an average of 0.77%
increment in brightness for unroughened LED. A separate study on using sodium
hydroxide (NaOH) for post LED fabrication cleaning was also conducted. A new
discovery was achieved where the brightness of the LED was increased by 5.05%
and 1.11% for roughened and unroughened LED respectively. The short cleaning
time (30 seconds) with NaOH was to clean the LED surface from contaminants. This
suggests that the presence of the SMRSG which is an MRS and cleaning of the LED
surface was able to change the LEE of the LED.