Effects of Hydrogen Treatment in Barrier on the Electroluminescence of Green InGaN/GaN Single-Quantum-Well Light-Emitting Diodes with V-Shaped Pits Grown on Si Substrates

Effect of hydrogen (H_2) treatment during the GaN barrier growth on the electroluminescence performance of green InGaN/GaN single-quantum-well light-emitting diodes (LEDs) grown on Si substrates is experimentally investigated. We prepare two LED samples with different carrier gas compositions during the growth of GaN barrier. In the H_2 free LED, the GaN barrier is grown in full nitrogen (N_2) atmosphere. For the other H_2 treated LED, a mixture of N_2 and H_2 was used as the carrier gas. It is observed that V-shaped pits decrease in size after H_2 treatment by means of the scanning electron microscope. Due to the fact that the p-n junction interface would be closer to the p-GaN as a result of smaller V-shaped pits, the tunneling barrier for holes to inject into the InGaN quantum well would become thicker after H_2 treatment. Hence, the external quantum efficiency of the H_2 treated LED is lower compared to the H_2 free LED. However, LEDs would exhibit a better leakage behavior after H_2 treatment during the GaN barrier growth because of more effective blocking of the threading dislocations as a result of the H_2 etching at V-shaped pits.