Design of AlGaN-based quantum structures for low threshold UVC lasers

Abstract

The influence of the polarization field on the emission properties of the AlGaN-based quantum structures grown on AlN substrates was investigated as a function of well width, barrier width, and barrier height. A thin AlGaN well and a thin AlN barrier design reduced the polarization field to ∼0.5 MV/cm, resulting in an ultralow laser threshold of 3 kW/cm² in an optically pumped configuration. These experimental results were used to validate the simulation. In the next step, a structure with Al_0.7Ga_0.3N barriers was designed to support carrier injection with a minimal loss in optical performance. This structure showed a threshold of 7 kW/cm² under optical pumping and an estimated threshold current of 8 kA/cm² for the electric injection.