Characteristics of InGaN/GaN Light-Emitting Diode with Si δ-Doped GaN Contact Layer

We have investigated the characteristics of InGaN/GaN blue light-emitting diodes (LEDs) with a Si δ-doped GaN contact layer. The Si δ-doping of the GaN contact layer in the devices could enhance the Si doping concentration and improve the lateral conductivity in the GaN:Si contact layer without cracking. The operating voltage and dynamic resistance of LEDs with a Si δ-doped GaN contact layer were 3.65 V and 27 Ω at 20 mA, respectively. The operating voltage and dynamic resistance of conventional LEDs with a uniformly doped GaN:Si contact layer were 3.94 V and 32.3 Ω at 20 mA, respectively. Also, the leakage currents at a reverse bias of -10 V were 2.8 μA for δ-doped LEDs and 29 μA for uniformly doped LEDs. However, emission properties such as electroluminescence spectra and output power were not largely affected by utilizing a δ-doped GaN:Si contact layer in the devices.