Effect of multiple oxide layers in multi-junction VCSELs

There has been an increasing demand for Vertical Cavity Surface Emitting Laser (VCSEL) as a light source solution that offers higher power density, high conversion efficiency, and short pulse operation in these applications. In this report, we design and fabricate three-junction VCSELs with three oxide layers and a single oxide layer, aiming to explore the effects of oxide layers on device characteristics. The output characteristics indicate that the design with multiple oxide layers effectively confines carriers better, leading to higher conversion efficiency. However, in terms of thermal characteristics, the outcomes demonstrate that using only a single oxide layer effectively reduces resistance, resulting in better thermal performance in terms of heat dissipation characteristics. These results clearly demonstrate the pros and cons of multi-junction solutions and effectively provide information about multi-junction VCSELs for the next generation sensing applications.