The optical and structural study of InGaN/GaN MQWs in different well thickness

• Main Authors: Kun-hong Lin, 林坤宏
• Other Authors: Yen-sheng Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/16517852066601286516

碩士 === 義守大學 === 電子工程學系碩士班 === 97 === Light-emitting diodes with a low power, long life and fast response speed, at present the nitride of Ⅲ-Ⅴ group research for the most enthusiastic InGaN is a direct gap material, which has 3.4ev energy gap belonging to the ultraviolet range of blue. The blue light-emitting diode has great potential to be applied on full-color display devices, laser diodes, optical storage probe (Blu-ray DVD), and optical detectors. Due to the InGaN material has always lacked proper substrate, the high density dislocation had been produced, but the form of the In-rich region which is called quantum dots structure can effective confined carry and enhance the luminescence efficiency. Our research will focus on the form mechanism of In-rich region due to the higher quantum well thickness, which will be the driving force to form In-rich structures. In this study mainly research the effect of the efficiency in the different thickness of quantum wells. Microstructure analyses have shown the formation of indium-aggregated quantum-dot as clusters, due to the large lattice constant mismatch. This strain energy distribution not only affects the cluster formation, but also generates piezoelectric fields and hence the quantum confined Stark effect (QCSE). It is found the line-width of PL can be reduced by rapid thermal annealing（RTA）, leading to improve the optical characteristic of the LED structures. So this study mainly focuses on : (1)Phase Separation in various thickness of quantum well, it occurs different In-rich reaction. (2)Different strain energy levels will induce different dislocation structures. The two mechanisms will be discussed in detail with the effects of luminescence reaction on LED device. (3)The relation between optical characteristic and defect density after annealing treatment will also be compared in this study.