| 摘要 |
PURPOSE:To remove the mismatch of a lattice constant including the misfit caused by impurities, by changing the composition of at least one mixed crystal when combining compound semiconductors. CONSTITUTION:In order to coincide the lattice constants in the combination of the compound semiconductors, it is recommended that the forbidden bandwidth of the material used in a light emitting region is smaller than the forbidden bandwidth of the material in the other region, and the structure of the band in the light emitting region is of a direct transition type. The forbidden bandwidths of the two dimensional mixed crystal and the lattice constants of the known III-V group compound semiconductors are available, and the lattice constants of the mixed crystal of three element have a linear relationship between the compound semiconductor in accordance with Vegard's rule and the forbidden bandwidth can be approximated almost linearly. In the case of arbitrary ratio (x) of mixed crystal, the lattice constant and the forbiden bandwidth can be calculated by the specified equation. Therefore, the composition of the one mixed crystal is changed, the mismatch between the mutual lattice constants is eliminated, the carrier injection efficiency is enhanced, and the semiconductor laser having high efficiency and long life can be obtained. |
