Band Structure and Optical Gain in Staggered CdZnO/CdZnO/MgZnO Quantum-well Lasers

Band Structure and Optical Gain in Staggered CdZnO/CdZnO/MgZnO Quantum-well Lasers

The valence band structure and the optical gain characteristics of staggered CdZnO/CdZnO/MgGaN quantum well (QW) lasers are investigated using the multiband effective mass theory. These results are compared with those of conventional CdZnO/MgZnO QW lasers. The spatial separation between electron and hole wavefunctions is found to be reduced greatly with the inclusion of staggered InGaN layers. The heavy-hole effective mass around the topmost valence band is not affected by the inclusion of the staggered layer. The optical gain peak of a conventional QW structure rapidly decreases with increasing Cd composition. On the other hand, the reduction in the optical gain by the increase of the Cd composition is shown to be decreased greatly with the inclusion of a staggered QW structure. This can be explained by the fact that the internal field is reduced for a staggered QW structure.

The valence band structure and the optical gain characteristics of staggered CdZnO/CdZnO/MgGaN quantum well (QW) lasers are investigated using the multiband effective mass theory. These results are compared with those of conventional CdZnO/MgZnO QW lasers. The spatial separation between electron and hole wavefunctions is found to be reduced greatly with the inclusion of staggered InGaN layers. The heavy-hole effective mass around the topmost valence band is not affected by the inclusion of the staggered layer. The optical gain peak of a conventional QW structure rapidly decreases with increasing Cd composition. On the other hand, the reduction in the optical gain by the increase of the Cd composition is shown to be decreased greatly with the inclusion of a staggered QW structure. This can be explained by the fact that the internal field is reduced for a staggered QW structure.