InGaN/GaN multiple quantum wells with silicon delta doping in GaN barriers for light-emitting diodes

In this paper, silicon delta doping was incorporated in the GaN barriers of InGaN/GaN multiple quantum well (MQW) structures for blue light-emitting diodes. High-order satellite peaks from X-ray diffraction suggested indium incorporation in the hetero-structures. The indium content has been 0.171 and 0.192 for the silicon delta doped and undoped samples, respectively, by Vegard's rule. Thermodynamic analysis by Arrhenius plots of the temperature-dependent photoluminescence spectra revealed the enhancements in radiative recombination. The activation energy was shown to be 130 meV for the InGaN/GaN MQW structures with silicon delta doping. It was 110 meV for the undoped samples. The increase in the thermal activation energy was attributed to the supply of electrons from the silicon delta doping barrier region into the InGaN quantum wells. The hole-capturing by higher energy barrier in the valence band was also increased. Silicon delta doping suppresses carrier leakage by increasing exciton confinement, and therefore improves the quantum efficiency.