Carriers capturing of V-defect and its effect on leakage current and electroluminescence in InGaN-based light-emitting diodes

The effect of quantum well (QW) number on performances of InGaN/GaN multiple-quantum-well light-emitting diodes has been investigated. It is observed that V-defects, originated from various InGaN well layers intercepted by threading dislocations (TDs), increase in density and averaged size with more periods of QWs, resulting in larger reverse-bias leakage current and lower emission efficiency of light-emitting diodes. Conductive atomic force microscopy measurements demonstrate that V-defects may preferentially capture carriers, subsequently enhance local current and nonradiative recombinations at associated TD lines, which suggest that TD lines with V-defects at vertex have larger influence on emission efficiency than those without V-defects. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4772548]