High-power, multi-junction, 905 nm vertical-cavity surface-emitting laser with an AlGaAsSb electron-blocking layer

We report high-power multi-junction vertical-cavity surface-emitting lasers (VCSELs) with a significantly suppressed carrier leakage issue under high injection current and temperature. By carefully optimizing the energy band structure of quaternary AlGaAsSb, we obtained a 12-nm-thick AlGaAsSb electron-blocking layer (EBL) with a high effective barrier height (∼122 meV), a low compressive strain (∼0.99%), and a reduced electronic leakage current. The resulting three-junction (3J) 905 nm VCSEL with the proposed EBL exhibits an improved maximum output power (∼46.4 mW) and power conversion efficiency (PCE; ∼55.4%) during room-temperature operation. Also, it was found from thermal simulation that the optimized device shows more advantages over the original device during high-temperature operation. The type-II AlGaAsSb EBL provided an excellent electron-blocking effect and would be a promising strategy for multi-junction VCSELs to realize high-power applications.