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

Abstract

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 In 0.08 Ga 0.92 N 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 In 0.08 Ga 0.92 N 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 × 10 19 cm −3 , the output power is 138 mW, for 3 × 10 19 cm −3 doping it is 364 mW and for 5 × 10 19 cm −3 doping it increased to 556 mW. For the p-GaN EBL, the threshold current at 1 × 10 19 cm −3 is 319 mA, at 3 × 10 19 cm −3 doping it falls to 231 mA and for 5 × 10 19 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.

Controlling GaN-Based Laser Diode Performance by Variation of the Al Content of an Inserted AlGaN Electron Blocking Layer

“…In order to reduce electron leakage, people researchers have explored the optimization of the electron barrier. In these studies, researchers confirmed that the Al content in Al x Ga 1−x N EBL can be optimized for suppression of carrier leakage in the quantum well structure [17][18][19]. However, there are few studies on the regulating mechanism of Al content of the AlGaN EBL in various wavelength ranges and its effects on LD performance, resulting in a lack of horizontal comparisons and analyses.…”

Advantages of InGaN–GaN–InGaN Delta Barriers for InGaN-Based Laser Diodes

“…Many efforts have been made to improve the performance of GaN LDs, such as increased output power, decreased threshold current, and enhanced slope efficiency. Improved designs include various electron blocking layers (EBLs) for better suppression of electron leakage [ 7 , 8 , 9 ] and optimization of various waveguide layers (WLs) and cladding layers (CLs) to decrease internal optical absorption losses [ 10 , 11 , 12 ]. There has been less research on the multiple quantum well (MQW) active region of GaN LDs relative to that on GaN-based light-emitting diodes (LEDs) because the LD structure is much more complex.…”