本篇論文中，測試矽基板上再成長氮化鋁鎵/氮化鎵異質結構，發現未摻雜的氮化鎵通道層在現階段的成長環境下會成為元件的漏電路徑。
於矽基板上的p-GaN/AlGaN/GaN磊晶層製作HEMT元件，這部分的研究著重於解決關鍵製程上的問題，如p型歐姆接觸及p型氮化鎵蝕刻，在控制良好的製程下製作出HEMTs及LEHEMTs，其設計為Lg=3 um、Lgs=3 um以及Lgd=7 um，兩者的臨界電壓(threshold voltage)皆為-1.0 V，閘極電壓為1 V時定義其導通電阻(on-resistance, Ron)，LEHEMT為7.26 mΩ*cm2，HEMT為6.14 mΩ*cm2，其中LEHEMT擁有最大電流密度303.1 mA/mm，HEMT最大電流密度為114.8 mA/mm，由於LEHEMT汲極端有內建p型氮化鎵，其擁有2.0 V的導通電壓(trun-on voltage)。
在發光特性上，LEHEMT的發光峰值365.52 nm為近紫外光波段，半高寬(Full width at half maximum, FWHM)為8.2 nm意指此元件有良好的材料特性，發光波長也和氮化鎵發光二極體一樣隨溫度上升右移，此現象稱為紅移現象(red shift)。

In this study, the regrowth of AlGaN/GaN heteroepitaxy on the Si substrate were tested. We observed that the undoped-GaN channel layer with the current growth conditions is a critical leakage path for the device.
HEMT devices were fabricated with p-GaN /AlGaN/GaN epitaxial layers on Si substrate. This part of study focuses on solving the problems of the critical processes, for example, p-type ohmic contact and the etching of p-GaN. After controlling the critical processes, HEMTs and LEHEMTs were fabricated with Lg=3um, Lgs=3um, and Lgd=7um, both showing a threshold voltage (Vds=15V drain current criterion of 10 μA /mm) of -1.0V. Ron,sp , defined at a gate voltage of 1 V, is 7.263 mΩ*cm2 for the LEHEMT and 6.142 mΩ*cm2 for the HEMT. The maximum current density of the LEHEMT is 303.1 mA/mm, and the HEMT device is 114.8 mA/mm. With the built-in p-GaN on the drain, a 2.0 V turn-on voltage is needed for LEHEMT.
For the optical properties, the wavelength of the emitted light is 365.52 nm near ultraviolet light in the LEHEMT. The FWHM (Full width at half maximum) is 8.2 nm indicating the good material prop-erties of the device. The wavelength increases with the rise of the temperature which is usually observed in GaN LED and called red shift. 

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