中文摘要:
硒化鋅相關磊晶膜是極佳的藍光二極體材料. 而在生長硒化鋅相關磊晶膜的基板需考慮三個問題：（1）晶格匹配 （2）熱匹配 （3）內部擴散
以硒化鋅基板取代砷化鎵或砷化磷能避免異質磊晶所造成的晶格不匹配或熱膨脹係數不匹配的缺點. 但由於硒化鋅基板太貴且不易取得. 因此我們以剝離方式來得到硒化鋅基板. 另一個理由是因為硒化鋅的發光效率會被底下的砷化鎵基板限制住. 因為砷化鎵的能隙較低會吸收硒化鋅的光. 所以我們以一金屬/玻璃層來取代砷化鎵以作為反射層而將本來被吸收的光反射.
在這篇論文裡, 硒化鋅相關磊晶膜已成功的被氫氧化鈉與雙氧水體積4比1或氨水與雙氧水體積9比1的混和溶液從砷化鎵基板上剝離並將之以銦黏貼在玻璃上. 在成功剝離後, 由PL的光譜可以看出PL的強度和黃光區都會增強. 但是產生黃光區的缺陷可以由檸檬酸與雙氧水3比1的混合溶液而減少. 這個溶液還有助於硫硒化鋅的再生長. 利用有機金屬氣相沈積法再生長硫硒化鋅的最佳條件：硒化氫與硫化氫的比是4, 而二族與六族的比是12.5. 在77K光激發光光譜中Near-band-edge之光發射的波長為432nm且其半高寬為26.6meV.經過再生長後發現原先存在的DAP消失了,這代表薄膜的品質經過再生長後變好了.

ABSTRACT
ZnSe-based materials have excellent characteristics for blue light emitting devices. So the substrates used for the growth of ZnSe-based alloys are considered from three points of (1) lattice match, (2) thermal match, and (3) interdiffusion.
By replacing GaAs or GaP wafers by ZnSe substrates can avoid disadvantages of heteroepitaxy caused by lattice constant mismatch, by differential thermal expansion coefficients between substrate and epilayer. But the ZnSe substrate is cost too much. And it is not easy to achieve. So we choose the other way to get the substrate by Epitaxial Lift-Off (ELO). Another reason for this study is that the light extraction efficiency of these devices is limited by the optically absorbing GaAs substrate. So it can be improved by replacing GaAs with a new metal/glass substrate. The metallic interlayer can be used not only as an adhesive, but also as the reflective mirror to reflect light in the wafer-bonded LED structure.
In this study, ZnSe-epliayer have been successfully lifted-off from GaAs by etching solution (NaOH(1M): H2O2(30%) = 4:1 or NH4OH(30%): H2O2(30%) = 9:1) and adhered it onto Indium/glass. From PL spectra, the PL intensity and broad band increases after ELO. The broad band can be decreased by surface trimming of citric etching solution (C6H8O7: H2O: H2O2 = 30g: 30ml: 10ml). This etching process is helpful in regrown ZnSe-epilayer. Regrowth of ZnSSe with [H2Se]/[H2S]＝4 and II/IV=12.5, shows a NBE emission at 432nm with a FWHM of 26.6 meV at 77K PL spectrum. And the DAP is disappear after regrown. It means that the quality of ZnSe-epilayer becomes better after regrown.

CONTENTS

LIST OF FIGURES I
LIST OF TABLES III
ABSTRACT IV

1 INTRODUCTION 1
1-1Applications from Blue to Ultraviolet Light Emitting Devices 1
1-2 Promising Materials for Blue LEDs Nowadays 2
1-2-1 SiC Blue LEDs 2
1-2-2 GaN Blue LEDs 3
1-2-3 ZnSe Blue LEDs 4
1-3 Motivations for the Growth of Ternary and Quaternary
ZnSe-based Epilayers 5
1-4 Considerations of the Suitable Substrates 9
1-4-1 Problem of Lattice Mismatch 9
1-4-2 Problem of Thermal Mismatch 10
1-4-3 Problem of Interdiffusion 10
1-4-4 Selection of Substrate 11
1-4-5 The Motivations for ZnSe Epitaxial Lift-Off 12
1-4-6 Preparation of ZnSe surfaces for homoepitaxy 13
1-5 Requirements of Low-Temperature Growth 14

2 EXPERIMENTS 16
2.1 Growth System of OMCVD 16
2-1-1 Single Hot Zone and Cold Wall System 16
2-1-2 Simplicity, Flexibility and Versatility 17
2-1-3 Halide Free 17
2-1-4 Stoichiometry Control 17
2-1-5 Low Temperature and Low Pressure Growth 18
2-1-6 Capability of Multiple Heterostructures 18
2-2 Equipment of OMCVD 19
2-2-1 Design of Growth Reactor 19
2-2-2 Reactant Gas Handling System 20
2-2-3 Heating System 21
2-2-4 Exhaust Disposal System 21
2-2-5 Safety Consideration 21
2-3 Epitaxial Lift-Off Preparation 22
2-4 Multiple substrate treatment 23
2-4-1 Mechanical processing 23
2-4-2 Chemical processing 23
2-4-3 Selective etching 23
2-5 Surface preparation of ZnSe-based substrates for LP-OMVPE 24
2-6 Growth Procedure 24
2-6-1 Conventional LP-OMCVD Growth Procedure 24
2-6-2 Quality Evaluation of ZnSSe Epilayer 25

3 RESULTS AND DISCUSSION 26
3-1 Selective Etching 26
3-1-1 Epitaxial Lift-Off by NH4OH(30%): H2O2(30%) =
9:1(volume ratio) 26
3-1-2 Epitaxial Lift-Off by NaOH(1M): H2O2 (30%)=
4:1(volume ratio) 26
3-2 Morphology of GaAs etched by different etching solution 26
3-2-1 Morphologies of GaAs etched by NH4OH(30%): H2O2(30%)=
9:1(volume ratio) 27
3-2-2 Morphologies of GaAs etched by NaOH(1M): H2O2
(30%)= 4:1(volume ratio) 27
3-3 Surface Observation after ELO 27
3-3-1 Photograph of the ELO cross-sectional views. 27
3-3-2 Plan-view specimens 28
3-4 Thin Film Stress 29
3-5 Thin Film Warpage 30
3-6 The Result of PL Spectra 31
3-6-1 Optical Property 31
3-6-2 NH4OH(30%): H2O2(30%)=9:1(vloume ratio) 31
3-6-3 Trimming for surface of ZnSe-layer after ELO 33
3-6-4 Epitaxy ZnSSe on GaAs by OMVPE 34
3-6-5 Explanation of broad band emission 35
3-7 Different morphologies of ZnSe-epilayer etched by different
solutions 36
3-7-1 Morphology of ZnSe-epilayer etched by etching solution
NH4OH(30%):H2O2(30%)=9:1(volume ratio) 36
3-7-2 EDX analysis 37
3-7-3 Morphology of ZnSe-epilayer etched by etching solution
NaOH(1M): H2O2(30%)=4:1(volume ratio) 38
3-8 Blue shift 38
3-8-1 Phenomena of different sections after ELO by etching
solution NH4OH(30%): H2O2(30%)=9:1(volume ratio) 39
3-8-2 ELO by NaOH(1M): H2O2(30%) =4:1(volume ratio) 41
3-9 Re-grown 42
3-9-1 Surface preparation of ZnSe-epilayer substrate 42
3-9-2 Optical property at different baking temperature 42

4 CONCLUSIONS 44

FIGURES 46

LIST OF TABLES 86

APPDENIX 89

REFERENCES 97

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