Polarization-dependent optical characteristics of violet InGaN laser diodes

The polarization-dependent optical characteristics of violet InGaN laser diodes, such as band diagrams, emission wavelength, and threshold current, under different operation temperatures have been investigated numerically. Specifically, the normal and reversed polarizations are presented when the laser diodes with wurtzite structure are grown along Ga-face and N-face orientations, respectively. The simulation results show that the lowest threshold current is obtained for the double-quantum-well laser diode with normal polarization, while it is obtained for the single-quantum-well laser diode with reversed polarization. The main physical explanation for the phenomenon is due to effectively reduced electron leakage current, increased hole current density, and reduced Shockley-Read-Hall recombination rate within the active region as the idea of reversed polarization is considered.