| Summary: | 碩士 === 國立東華大學 === 電機工程研究所 === 89 === In this paper, we will describe a theoretical model systematically. The model can analysis any kind material of the quantum well lasers grown on arbitrarily oriented substrates. Now, we especially focus on researching the quantum well of the short wavelength (650 nm) lasers. We will describe to compute the band structures, momentum matrix elements, the gain spectra, the spontaneous emission rate and the radiative current density in detail. In this model, we consider many complex effects include the mixings among the valence bands, the effect of the quantum well grown on arbitrarily oriented substrates, the strain in the quantum well, the bandgap shrinkage effect due to carrier-carrier interaction and the lifetime broadening resulting from the scattering process.
We will use Luttinger Hamiltonian and Bir-Pikus Hamiltonian put in the effect mass equation. To get in on coordinate transformation matrix computing the band structures grown on arbitrarily oriented substrates. Further we use the present energy state and wave function to compute momentum matrix elements, including polarization that is TE mode and TM mode. After we find the carrier distribution probability and the concentration are presented, we then use the present momentum matrix elements to compute the gain spectra and the spontaneous emission rate. The resulting spontaneous emission rate can get the radiative current density further.
The investigative purpose in this paper is that we compute the quantum well of 650 nm lasers grown on arbitrarily oriented substrates and its the relationship of the optical gain and the radiative current density, then get the best structure. On the other hand, we have found the TE optical gain of the quantum well grown on [001] and [111]-oriented substrates is isotropy, but the other is anisotropy. For example, in [11l]-oriented family, the isotropy of the TE optical gain in the quantum well grown on [110]-oriented substrates is the most obvious, and the maximum on -oriented. This is the most important discovery. Especially apply to the stabilized output light polarization direction of vertical cavity surface emitting lasers (VCSEL) on the reading head of DVD system is very important.
|
|---|
