低效率滑落效應與高調制頻寬之薄p-型層發光二極體(2/2)

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Project title/計畫英文名

Project Number/計畫編號

105-2622-E-002-012-CC2

Translated Name/計畫中文名

低效率滑落效應與高調制頻寬之薄p-型層發光二極體(2/2)

Project Principal Investigator/計畫主持人

CHIH-CHUNG YANG

Funding Organization

National Science and Technology Council

Start date/計畫起

01-11-2016

Expected Completion/計畫迄

31-10-2017

摘要：本計畫內我們提出鎂摻雜調制生長技術來形成p-型氮化鎵/u-型氮化鎵交替層結構，以增大發光二極體內p-型層的電洞遷移率，因而降低其電阻率。電阻率能夠降低係利用高鎂摻雜的p-型氮化鎵層來產生高濃度的電洞，然後電洞擴散到無摻雜的u-型氮化鎵層得以高遷移率移動。因為使用分子束磊晶生長這種交替層的p-型層結構沒有鎂殘留的問題，也不需要p-型激發程序，我們將先利用分子束磊晶生長來展示這種低電阻率的p-型層，然後再利用實用性的有機金屬氣相沉積方法生長這種p-型層供發光二極體應用。利用有機金屬氣相沉積方法生長時，我們也將考慮鎂在生長腔體內殘留(俗稱「鎂記憶」)、鎂在磊晶層內擴散、提早通入鎂的效果。其中「鎂記憶」可能會降低上述交替層結構的層間鎂含量對比，而提早通入鎂可以大幅提高鎂摻雜濃度，乃相當有用的技術。此外我們也將利用在成份漸變的氮化銦鎵及氮化鋁鎵層內的極化感應特性來增加電洞濃度。將這種低電阻率的p-型層用於發光二極體上，p-型層的厚度就可以降低，如此一來因為發光二極體的量子井結構和表面銀奈米顆粒的距離變小，使得其間的表面電漿子耦合效果加強。經由表面電漿子耦合，發光二極體的效率滑落效應可以降低，而其調制頻寬可以提高。
Abstract: In this project, we propose the growth technique of Mg-doping modulation to form a p-GaN/u-GaN alternating-layer structure for increasing the hole mobility and hence decreasing the resistivity of the p-type layer of a light-emitting diode (LED). The resistivity can be reduced based on the concept that high-concentration holes are generated in the highly Mg-doped layers and holes are diffused into the un-doped layers for high-mobility transport. The implementation of a low-resistivity p-type layer will be first demonstrated with molecular beam epitaxy because it does not have the problem of residual Mg atoms and does not need the process of p-type activation. Metalorganic chemical vapor deposition (MOCVD) will then be used to grow a practically useful p-type layer of low resistivity for LED application. In using MOCVD for growth, the factors of Mg memory, Mg diffusion, and Mg pre-flow will be investigated. Mg memory may lead to a lower Mg concentration contrast between the neighboring p-GaN and u-GaN layers in the aforementioned layered structure. However, the Mg pre-flow technique is quite useful for increasing Mg incorporation. The technique of polarization-induced hole generation in content-gradient InGaN and AlGaN will also be used for increasing the hole concentration. With such a low-resistivity p-type layer, its thickness in an LED can be reduced. In this situation, by forming Ag nanoparticles (NPs) on the p-type layer of an LED, the surface plasmon (SP) coupling effect can be significantly enhanced due to the shorter distance between the Ag NPs and the quantum-well structure of the LED. Through the SP coupling effect, the LED efficiency droop effect can be reduced and the LED modulation bandwidth can be increased.

Keyword(s)

發光二極體
p-型氮化鎵
鎂摻雜調制
表面電漿子
效率滑落效應
調制頻寬
light-emitting diode
p-GaN
Mg-doping modulation
surface plasmon
efficiency droop effect
modulation bandwidth

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低效率滑落效應與高調制頻寬之薄p-型層發光二極體(2/2)

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