论文部分内容阅读
GaN基激光器具有广泛的应用。如何获得平整腔面是蓝宝石衬底上制作GaN激光器的困难之一。通过对解理面的分析和不同衬底厚度时腔面形貌的比较,发现减薄衬底可以有效降低腔面粗糙度。当外延片厚度减薄至50μm时,获得近似镜面的腔面。激光器的测量证实了腔面的改善可以降低阈值电流,增加斜率效率。利用二维光波导模型计算了脊形高度对限制因子和远场分布的影响。计算结果说明,增加脊形高度可以增加限制因子,降低远场纵横比。通过测量具有不同脊形高度的器件,证实了脊形高度增加,阈值电流降低、远场纵横比减小。
GaN-based lasers have a wide range of applications. How to obtain a planar cavity is one of the difficulties in fabricating a GaN laser on a sapphire substrate. By analyzing the cleavage planes and comparing the surface topography of different substrate thickness, it is found that the substrate thinning can effectively reduce the cavity surface roughness. When the thickness of the epitaxial wafer is reduced to 50 μm, an approximately mirror-like cavity surface is obtained. Measurement of the laser confirmed that the improvement of the cavity surface can reduce the threshold current and increase the slope efficiency. The effect of ridge height on the limiting factor and the far-field distribution was calculated using a two-dimensional optical waveguide model. The calculation results show that increasing the ridge height can increase the limiting factor and decrease the far-field aspect ratio. By measuring devices with different ridge heights, it was confirmed that the ridge height increased, the threshold current decreased, and the far-field aspect ratio decreased.