Application of Solution-Processed Zinc Oxide on Gallium Nitride Epitaxy
Date Issued
2014
Date
2014
Author(s)
Wu, Hao-Yu
Abstract
The study of this thesis is to investigate the growth of gallium nitride (GaN) via pulsed laser deposition (PLD) on the solution processed zinc oxide (ZnO) buffer layer via hydrothermal method. After GaN growth on ZnO, we investigate the solution lift-off and transferring GaN thin film to metal substrate with ZnO layer etched by HCl solution.
In the first part of the thesis, we present the highly c-oriented and crystallinity ZnO film via hydrothermal method in the condition of 100mM solution; 90oC environment and 10 hours growth.
Next, we discover the best N2 environment of PLD-GaN growth with Ga/N ratio almost equal to 1 measured by energy dispersive spectrum (EDS). However, the Raman spectrum and the X-ray diffraction spectrum(XRD) of GaN thin film shows that the structure of GaN includes both wurzite and rock-salt structure. The rock-salt structure can be reduced by adding up the growing temperature of PLD to 1100oC. Unfortunately, crack appears on the GaN/ZnO film with over 1000oC growth.
In order to avoid cracks, GaN film is grown in a lower temperature 800oC then anneal instead. The wurzite structure signal of GaN appears in the Raman spectrum after the 900oC annealing for 30 mins.
In the other part of the thesis, we demonstrate the solution lift-off and transfer the GaN thin film to electroplating copper substrate from sapphire and confirmed it with scanning electron microscopy(SEM) and EDS.
The last part of the thesis, we propose the idea of growing non-polar ZnO on Si substrate with groove structure in order to reduce the quantum confined Stark effect (QCSE) of LED. The good step coverage of spin-coating ZnO seed layer allows us to grow ZnO nano-rods with non-polar faces on the top on the side wall of Si grooves. After removing the gold layer and the polar ZnO in the same time, we present the ZnO with non-polar face on the top.
Subjects
溶液製程
氧化鋅
氮化鎵
脈衝雷射沉積
非極性
溶液剝離
Type
thesis
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