Numerical investigation on the negative characteristic temperature of InGaN blue laser diodes

GaN-based blue laser diodes (LDs) can exhibit peculiar temperature characteristics such as quite a high characteristics temperature (T ₀ ) or even negative T ₀ . The author investigates the temperature-dependent device characteristics of blue LDs having InGaN double quantum-well (QW) structures using numerical simulations. As the n-type doping concentration of a barrier layer between QWs increases, negative T ₀ can be observed, which is found to originate from the increase of gain at the n-side QW with temperature as a result of the improvement of hole transport in QWs with temperature.