GaN-ZnO异质结发光二极管的性能调控

摘要ZnO与GaN晶格失配仅为1.9%，因此n-ZnO/p-GaN被认为是最佳的异质结结构。h-BN具备宽禁带和低电子亲和势的特征，非常适合作为电子阻挡层。本文针对n-ZnO/p-GaN异质结进行了研究，得到以下成果：一、n-ZnO/p-GaN和n-ZnO/h-BN/p-GaN异质结LED的制备。利用商业化生长在蓝宝石基片上的p-GaN作为衬底，利用磁控溅射法沉积ZnO，衬底转移法转移生长好的h-BN，经过退火过程和欧姆接触的制备后获得了完整的器件。通过扫描电镜、XRD等表征手段检验了所沉积的薄膜的质量，证明GaN和ZnO均表现出一定的择优取向。二、测试两种器件的I-V曲线、EL图谱。两种结构均表现出较好的整流特性，开启电压增大。通过对比两者的EL图谱，研究器件的电致发光，发现发射峰发生蓝移，半高宽减少。基于器件的能带示意图，证明插入h-BN电子阻挡层可以得到ZnO的蓝紫光发射。26715
毕业论文关键词n-ZnO/p-GaN异质结n-ZnO/h-BN/p-GaN异质结电子阻挡层电致发光
Title   Performance control of GaN-ZnO heterojunction   light emitting diode
Abstract
n-ZnO/p-GaN is considered as the optimal heterojunction structure because
lattice mismatch rate of ZnO and GaN is only 1.9%. h-BN is suitable to be used
as the electron blocking layer for its characteristics of wide band gap and low
electron affinity. This paper is concentrated on n-ZnO/p-GaN heterojunction,
and the results are as following:
1. Fabrication of n-ZnO/p-GaN and n-ZnO/h-BN/p-GaN heterojunction LEDs.
Commercial p-GaN on a sapphire substrate was used as the substrate. Magnetron
sputtering was utilized in order to grow ZnO thin films and grown h-BN was
transferred to p-GaN substrate. After annealing process and fabrication of ohm
contacts, the complete devices were obtained. With the scanning electron
microscope and the X-ray diffraction, the quality of deposited films were tested
and proved to exhibit some preferred orientation.
2. I-V curve and EL spectra of two kinds of devices were tested. Two structures
showed good rectifying characteristics and increased turn-on voltage.
Compared with the EL spectra, the electroluminescence properties have been
studied. It turned out that emission peaks ware blue-shifted and FWHMs were
reduced. With h-BN inserted as electron blocking layer, the blue-violet
emissions from ZnO layer has been understood by analyzing the energy band
diagrams.
Keywords    n-ZnO/p-GaN heterojunction；n-ZnO/h-BN/p-GaN heterojunction；Electron
blocking layer；Electroluminescence.
目次
1   绪论    1
1.1 LED概述    1
1.2 n-ZnO/p-GaN异质结 LED研究进展    4
1.3   论文的选题意义与研究内容 . 8
2 ZnO/GaN 异质结 LED 的制备及表征 . 10
2.1 n-ZnO/p-GaN异质结发光二极管的制备 . 10
2.2 n-ZnO/h-BN/p-GaN 异质结发光二极管的制备 . 11
2.3   器件的表征手段 . 12
3   实验结果及其分析    16
3.1 h-BN薄膜的表征 . 16
3.2   扫描电镜结果分析 . 18
3.3 XRD 结果分析 . 20
3.4   拉曼光谱（Raman）结果分析 . 21
3.5   光致发光（PL）结果分析    23
3.6   器件的 I-V曲线和 EL图谱    24
3.7   器件正向偏压下的发光原理 . 26 GaN-ZnO异质结发光二极管的性能调控:http://www.751com.cn/cailiao/lunwen_20980.html