| Summary: | 碩士 === 國立交通大學 === 光電工程研究所 === 105 === In this paper, we first covered the metal contact to improve the L-I curve of the oscillation behavior. And at the same time found that the impact of metal contact on the laser characteristics. When we covered the metal contact with aperture on the structure, will greatly increase the laser threshold. However, after the metal contact away from the structure, this way can get a compromise laser threshold from 230mA down to 28mA and is not far from the sample with no metal contact(20mA).
Then we use this way to the structure of the photonic crystal from 1D to 2D and successfully produced the 2D PhC sample. It is found that in the platform structure with such a large aspect ratio, the 2D laser threshold is higher (50mA) and the divergence angle (1.9o, 9.7o) is similar to the 1D laser(1.4o, 10.4o). Using the simulation software COMSOL, we can see that the 2D Q value (297) is much smaller than the 1D Q value (10817) in the structure with such a large aspect ratio, and the field distribution is longer in the shorter width-direction , this simulation result indicated that the divergence angle corresponding to the far-field measurement has a relationship similar to the Fourier transform from near field. This is because the 2D structure in such a large aspect ratio, in which one direction can not effectively play 2D coupling characteristics. (131oC and 121oC) and T0 to observe almost the same, that is the temperature characteristics caused by the luminescent material itself, and the photonic crystal structure and dimensions are not much relationship.
In the end we optimize the crystal conditions step by step, first change the etching depth, so that the optical excitation can be achieved. Then different current confinement structures were fabricated and compared. The device with current confine aperture has better current spreading situation. In the future work, we hope to simulate the current path and setting the light source at difference position in the PhC strudture. This can help ue understand the complete electrically pumped luminescence.
|
|---|
