Effects of a highly Si-doped GaN current spreading layer at the N+-GaN/multi-quantum-well interface on InGaN/GaN blue-light-emitting diodes

Highly Si-doped GaN thin current spreading layer (CSL) with various carrier concentrations were inserted before the n{sup +}-GaN/multi-quantum-well (MQW) interface controlled by the growth rate and the modulated Si-doping in InGaN/GaN blue light-emitting diodes (LEDs), and their effects were investigated by using capacitance-voltage (C-V), current-voltage (I-V), and output power measurements. The LEDs with a highly Si-doped CSL show enhanced I-V characteristics and increased output power with increasing carrier concentration up to some critical point in the CSL. This means that proper high Si-doping in some limited area before the interface may enhance the device performance through the current spreading effect.