H^+ Passivation of Poly-Si Solar CellsProcessed by Different Annealing Processes

The effects of different annealing processes on the photovoltaic (PV) properties and the spectral response as well as minority carrier lifetime in the bulk of unanalyzed PF5 ion implantation poly-Si solar cells were investigated. The different hydrogen passivation effects of defects in poly-Si induced by three heat treatment processes are reported. We used RTA-rapid thermal annealing, YAG pulse laser annealing and CTSA-classical three-step annealing for this study. The results show that cells processed by RTA (800°C, 4 sec) achieved the best PV properties and spectral response among all annealed samples. Under this precess condition, no or few defects were induced in bulk. While RTA (>-850°C for 4 sec), CTSA as well as YAG laser processes induced defects of different nature and concentration in the bulk of cells. It is further shown that hydrogen ion implantation significantly improved, the performances of poly-Si cells. It is able to efficiently remove the YAG laser induced defects in bulk. However, it cannot completely passivate the defects induced by CTSA and RTA processes.

基于GaN微米阵列结构的单芯片白光LED有源区InGaN/GaN多量子阱结构设计

通过模拟仿真对双波长堆叠的c面InGaN/GaN多量子阱(MQWs)发光二级管的载流子浓度、自发辐射复合率以及极化电场等进行了研究。结果表明,通过调节双波长堆叠的InGaN多量子阱的阱层和垒层厚度,可调控载流子特别是空穴在量子阱有源区的分布,实现双波长发光峰比例调制。进而考察了在相同外延条件下生长的半极性面InGaN/GaN堆叠量子阱LED的发光特性。在此基础上,提出基于多波长堆叠InGaN/GaN多量子阱结构的c面和{1011}或{1122}半极性面混合的单芯片白光LED设计方案,通过调节c面发光光谱在混合光谱中的比例,可获得覆盖大部分可见光波段、色温从4500~9000 K可调、且显色指数最高可达91.3的白光。