量子调控高铝组分氮化物基深紫外LED光提取效率

Light extraction efficiency of high-aluminium nitride-based deep ultraviolet (UV) LEDs is very low , in part because light emission of high-aluminum nitrides along c-axis is very weak. This project is to explore structures of deep UV LEDs with high light extraction efficiency. We use high-aluminum nitride superlattice as the potential well in the active region of c-plane nitride-based deep UV LEDs . Thickness and Al component of the superlattice are employed to regulate the quantum confinement effect and stress effect on the energy band of the superlattice, and thereby modulate the light emission of UV LEDs. By quantum control of energy band of the active region, emission intensity of the superlattice along c-axis can be enhanced, thus improving light extraction efficiency of deep UV LEDs. The project uses patterned substrate technology, angle-resolved PL spectra , EL spectra, XRD, TEM and other means to study high-aluminium nitride-based deep UV LEDs, conducting the following studies: 1)to explore the impact of thickness and Al composition in high -aluminum nitride superlattice on its micro-structure and optical properties; 2)to obtain strain coefficient of energy band of high-aluminum nitride superlattice and its relationship with thickness and Al component in the superlattice; 3)to explore relationship between the structure of the superlattice and the light properties of the deep UV LED which uses the superlattice as the potential well of the active region. This study helps to get an LED structure with high light extraction efficiency, and provides experimental data to the study of light extraction efficiency of deep UV LEDs.

高铝组分氮化物基深紫外LED的光提取效率非常低，原因之一是高铝组分氮化物沿c轴方向发光很弱。本项目以探索出具有高光提取效率的深紫外LED结构为目标，使用高铝组分氮化物超晶格作为c面氮化物基深紫外LED有源区的势阱，利用量子限制效应和应力对高铝组分氮化物超晶格的能带进行量子调控，增强超晶格沿c轴的发光强度，进而提高深紫外LED光提取效率。本项目利用图形衬底技术、角分辨PL谱、EL谱、XRD、TEM等手段，对高铝组分氮化物超晶格和深紫外LED进行以下研究：1）探索高铝组分氮化物超晶格各层厚度和Al组分对其微结构和光学性质的影响；2）确认高铝组分氮化物超晶格能带的应力系数及其与超晶格厚度、铝组分的关系；3）探索以高铝组分氮化物超晶格作为有源区势阱的深紫外LED的光学性质与超晶格的结构的关系。本项目有助于获得具有高光提取效率的深紫外LED结构，同时为深紫外LED光提取效率研究提供实验数据。

本课题主要研究内容包括：高铝组分深紫外发光的氮化物超晶格量子阱结构的生长和优化；厚度、组分和应力等对其晶体质量、能带和深紫外发光性质的影响和调控。三年来，经过课题组成员的努力，在氮化物材料及氮化物基紫外发光结构的生长和晶体质量、发光性质调控等方面取得了若干进展。项目执行期间，共发表学术论文8篇，其中SCI收录论文5篇；获批中国发明专利3项；毕业博士研究生1人、毕业硕士研究生3人；课题组成员参加国内学术会议6人次。本课题完成了计划任务书规定的研究任务。