Effects of electron blocking layer configuration on the dynamics of laser diodes emitting at 450 nm

In this paper, a theoretical study is presented, analysing the Al x Ga(1−x)N electron blocking layer (EBL) at different Al content and Mg-doping levels for the InGaN-based laser diode (LD) emitting at 450 nm. It is observed that the performance of LDs not only depends on the Al content in the EBL but also on the Mg doping levels in the EBL and the In content in the InGaN waveguide. The optimum selection of AlGaN EBL strongly depends upon the In content in the InGaN waveguide. It is found that, for an In0.08Ga0.92N waveguide, the higher Al content in the EBL degrades the performance due to the increase in leakage current, thus an Al-free EBL i.e. a GaN EBL, is optimal for an In0.08Ga0.92N waveguide. However, the increased Mg doping in the p-GaN (Al = 0) EBL shows improvement in the performance of LDs. For the p-GaN EBL with a Mg-doping level of 1 × 1019 cm−3, the output power is 138 mW, for 3 × 1019 cm−3 doping it is 364 mW and for 5 × 1019 cm−3 doping it increased to 556 mW. For the p-GaN EBL, the threshold current at 1 × 1019 cm−3 is 319 mA, at 3 × 1019 cm−3 doping it falls to 231 mA and for 5 × 1019 cm−3 doping it is 227 mA. For the heavily doped p-GaN EBL, the threshold current dependency is negligible at higher Al content in the EBL, but power output shows a strong dependency on the Al content. In the case of an In-free waveguide i.e. a GaN waveguide (In = 0), the performance of the LD is optimal at 15% Al content in the EBL.