Improved Hole Transport by ${\rm p}\hbox {-}{\rm In}_{x}{\rm Ga}_{1-x}{\rm N}$ Layer in Multiple Quantum Wells of Visible LEDs

Studied is the effect of indium (In) mole fraction in p-In^xGa_1-xN:Mg layers with 0 ≤ x_In ≤ 0.035 on hole injection and transport behaviors in InGaN/GaN multiple quantum wells (MQWs) using dual-wavelength and triple-wavelength active regions. Electro-optical characteristics of light-emitting diodes containing p-layers with different In content and with silicon doping in selected QW barriers (QWBs) are compared to evaluate hole transport in the active region. The results show that enhanced hole transport and corresponding more uniform distribution of holes across the MQW region are achieved by increasing x_In in the p-In_xGa_1-xN:Mg layer, possibly due to modification in energy of holes by a potential barrier between the p-InGaN and GaN QWB.