Design and Optimization for AlGaN‐Based Deep Ultraviolet Fabry–Perot Laser Diodes

Abstract

Abstract In this work, AlGaN‐based deep ultraviolet Fabry–Perot (FP) laser diodes (DUV LDs) are designed by using Technology Computer Aided Design (TCAD) simulations, and the physical models for DUV LDs are also developed. It is found that the optical absorption in the p‐region significantly increases the optical loss and reduces the laser power. Hence, properly increasing the Al composition for the p‐waveguide (p‐WG) and the p‐type cladding layer (CL) helps shift the optical field to the n‐region, which is effective in decreasing the free‐carrier absorption in the p‐region. However, if not properly optimized, this will decrease the optical confinement factor, which will decrease the stimulated recombination rate between electrons and holes. Then, the electron leakage becomes significant. The studies show that the p‐electron blocking layer (p‐EBL) will not strongly affect the optical field profiles. Hence, the Al composition in the p‐EBL has more freedom for electrical optimization. Therefore, a compromised design is required so that both the optical and the electrical properties can be improved.

Keywords

• AlGaN‐based deep ultraviolet Fabry–Perot laser diodes
• electron leakage current
• free‐carrier absorption
• optical field regulation