UV Electroluminescence and Structure of n-ZnO/p-GaN Heterojunction LEDs Grown by Atomic Layer Deposition
UV Electroluminescence and Structure of n-ZnO/p-GaN Heterojunction LEDs Grown by Atomic Layer Deposition
复制标题
DOI：
10.1109/jqe.2009.2025250
复制
发表时间：
2010-02
影响因子：
2.5
通讯作者：
Hsing-Chao Chen;Miin-Jang Chen;M. Wu;Wei-Chih Li;H. Tsai;J. Yang;H. Kuan;M. Shiojiri
中科院分区：
文献类型：
--
作者：
Hsing-Chao Chen;Miin-Jang Chen;M. Wu;Wei-Chih Li;H. Tsai;J. Yang;H. Kuan;M. Shiojiri
采用原子层淀积技术和快速热退火（RTA）技术生长了用于n-ZnO/p-GaN异质结LED的高质量ZnO外延层。X射线衍射测试表明，ZnO外延层具有较高的结晶度，且具有c轴取向。透射电子显微镜图像显示ZnO层是单晶，仅包括少数幸存的穿透位错，其产生于通过金属有机化学气相沉积在c-Al 2 O3衬底上沉积的GaN层中，并且其中大部分在n-ZnO/p-GaN界面处被消除。在n-ZnO和p-GaN层之间观察到由RTA处理引起的4-5 nm厚的界面层。在10 mA左右的低注入电流下，实现了ZnO在391 nm处的室温紫外电致发光。结果表明，n-ZnO和p-GaN在425 nm附近的电致发光之间的竞争可能是由于ZnO/GaN界面态的存在以及n-ZnO和p-GaN之间载流子浓度和发光效率的差异造成的。
Atomic layer deposition technique and subsequent rapid thermal annealing (RTA) were implemented to grow high-quality ZnO epilayers for the fabrication of n-ZnO/p-GaN heterojunction LEDs. The X-ray diffraction measurement reveals that the ZnO epilayer has high crystallinity with c axis orientation. Transmission electron microscopy images present that the ZnO layer is a single crystal, including only a few survivals of threading dislocations, which were generated in the GaN layer deposited by metal-organic chemical vapor deposition on the c-Al2O3 substrate and most of which were eliminated at the n-ZnO/p-GaN interface. An interfacial layer 4-5 nm thick caused by the RTA treatment was observed between the n-ZnO and p-GaN layers. Room temperature UV electroluminescence (EL) at 391 nm from ZnO was achieved at a low injection current about 10 mA. It is concluded that the competition between the ELs from the n-ZnO and p-GaN (around 425 nm) may be ascribed to the ZnO/GaN interface states coupled with the differences between the n-ZnO and p-GaN in carrier concentration and light emission efficiency.