Numerical simulation of 405-nm InGaN laser diodes with polarization-matched AlGaInN electron-blocking layer and barrier layer

For III-nitride compound materials, the existence of spontaneous and piezoelectric polarizations results in strong electrostatic fields, which might strongly affect the optical properties of 405-nm InGaN laser diodes. In this work, for polarization-free purpose, the use of polarization-matched AlGaInN electron-blocking layer and barrier layer in the violet InGaN multiple-quantum-well laser diodes is proposed. The laser performance and optical characteristics of the violet laser diodes are numerically evaluated by using the LASTIP (abbreviation of LASer Technology Integrated Program) simulation program. The simulation results show that, when the original Al0.20Ga0.80N electron-blocking layer is replaced by the polarization-matched Al0.39Ga0.49In0.12N electron-blocking layer, the laser performance is slightly improved. However, on the other hand, when compared to the original InGaN laser diode, the violet InGaN laser diode with a polarization-matched Al0.33Ga0.45In0.22N barrier layer possesses an increase of the threshold current and a decrease of the slope efficiency. It is presumably due to the fact that the effective potential height of conduction band at the interface of barrier and electron-blocking layer is reduced, and the electron leakage current is correspondingly enhanced when the polarization-matched barrier layer is utilized.