Low-threshold AlGaN-based deep ultraviolet laser enabled by a nanoporous cladding layer
Yongming Zhao, Liqiong Deng, Feng Wu, Zhihua Zheng, Pengcheng Jian, Weijie Liu, Zhenyu Chen, Shizhou Tan, Peng Meng, Wei Guo, Changqing Chen, Jiangnan Dai
Abstract
We demonstrated an AlGaN-based multiple-quantum-well (MQW) deep ultraviolet (DUV) laser at 278 nm using a nanoporous (NP) n-AlGaN as the bottom cladding layer grown on the sapphire substrate. The laser has a very-low-threshold optically pumped power density of 79 kW/cm 2 at room temperature and a transverse electric (TE)-polarization-dominant emission. The high optical confinement factor of 9.12% benefiting from the low refractive index of the nanoporous n-AlGaN is the key to enable a low-threshold lasing. The I–V electrical measurement demonstrates that an ohmic contact can be still achieved in the NP n-AlGaN with a larger but acceptable resistance, which indicates it is compatible with electrically driven laser devices. Our work provides insights into the design and fabrication of low-threshold lasers emitting in the DUV regime.