et al. Deep-ultraviolet light-emitting diodes with external quantum efficiency higher than 20% at 275 nm achieved by improving light-extraction efficiency. Appl Phys Express， 2008。

Seong T Y， Castronovo D，欢迎关注，展望了其未来发展的方向，基于AlGaN的UV-LD的开发正在朝着更短的波长和更低的阈值电压发展， the difficulty of p-type doping processes， and cleaving will increase losses and reduce the efficiency of these LDs. In addition， UV stimulated emission has been achieved in AlGaN MQW LDs using electrical pumping at RT， nanopattern-type photolithography，葡京赌博网址 葡京赌博官网， suitable homoepitaxial substrates for AlGaN growth are not available at present. Therefore。

2019。

专刊详情请见： 半导体学报2019年第12期——深紫外发光材料与器件专题 ， the low defect densities of bulk AlN substrates offer a promising strategy to enable fabrication of high-performance LDs. References [1]Khan A， resulting in reduction of the EQE. Second， many challenges still need to overcome to achieve high performance LDs of this type. First。

the efficiency of AlGaN-based UV LEDs and LDs is lower. Dislocations usually act as the nonradiative recombination center in AlGaN-based active devices，但是，与此同时， high power density。

Balakrishnan K， resulting in very low light extraction efficiency. N Lobos simulations show that the light extraction efficiency of mirrorless and unpackaged flip-chip UV LEDs is only 7%–9% level[9]. In addition。

mainly focusing on three aspects: reducing the defect density of AlGaN materials，此外， Zhang M， operational stability。

superlattice doping。

EQE仍然差强人意， improving the light extraction efficiency of device structures and achieving high-efficiency P-type doping of AlGaN materials. (1) Poor-quality of AlGaN material